Bulletin IX.I.IN'OZS rattxra.! History Survey 1 T r L BULLETIN A Survey of the Mussels (Unionacea) of the Illinois Riven a Polluted Stream am C. Starrett HMURMWSTORnURVEK JUN 23 1971 UBR^RY OF ILLINOIS RTMENT OF REGISTRATION AND EDUCATION IRAL HISTORY SURVEY DIVISION INA, ILLINOIS ''^ 4 1B71 VOLUME 30, ARTICLE 5 FEBRUARY, 1971 ILLINOIS >3'a*tix]:*a.l History Sux^vey BULLETIN' illiam C. Starrett A Survey of the Mussels (Unionacea) of the Illinois Riven a Polluted Stream ME OF ILLINOIS EPARTMENT OF REGISTRATION AND EDUCATION ATURAL HISTORY SURVEY DIVISION RBANA, ILLINOIS VOLUME 30, ARTICLE S FEBRUARY, 1971 STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION BOARD OF NATURAL RESOURCES AND CONSERVATION William H. Robinson. Chairman: Thomas Park. Ph.D., Biology; L. L. Sloss. Ph.D., Geology; Roger Adams. Ph.D..D.Sc.. Chemistry; Robert H. Anderson, B.S.C.E., Engineering; Chables E. Olmsted, Ph.D Foreetry; W. L. Everitt, E.E., Ph.D., Representing the President of the University of Illinois: Roger e! Beyler, Ph.D., Representing the President of Southern Illinois University. NATURAL HISTORY SURVEY DIVISION, Urbana. Illinois SCIENTIFIC AND TECHNICAL STAFF George Sprugel, Jr., Ph.D., Chief Alice P. Campbell, B.A., Secretary to the Chief Section of Economic Entomology William H. Luckmann, Ph.D., Entomologist Willis N. Bruce, Ph.D., Entomologist Wayne L. Howe, Ph.D., Entomologist Stevenson Moore, III, Ph.D., Entomologist, te Ex- EUGENE B. HIMELICK, Ph.D.. Plant Pathologist R. Dan Neely, Ph.D., Plant Pathologist D. F. SCHOENEWEISS, Ph.D., Associate Plant Pathol- ogist J. Leland Crane, Ph.D., Assistant Mycologist Walter Haktstirn, Ph.D., Assistant Plant Pathol- ogist Howard B. Petty, Ph.D., Entomologist, Extension James E. Appleby, Ph.D., Associate Entomologist Edward J. ARMBRUST, Ph.D., Associate Entomologist Marcos Kocan. Ph.D.. Associate Entomologist Joseph V. Maddox. Ph.D., Associate Entomologist Ronald H. Meyer, Ph.D.. Associate Entomologist Robert D. Pausch, Ph.D., Associate Entomologist Ralph E. Sechriest, Ph.D., Associate Entomologist George L. Godfrey, Ph.D., Assistant Entomologist Clarence E. White. B.S., Assistant Entomologist Keln S. Park. M.S., Assistant Chemist Sue E. Watkins, Supervisory Assistant Roscoe Randell, Ph.D., Assistant Professor, Exten- Donald E. Kuhlman, Ph.D., Instructor, Extension Tim Cooley. M.A.. Assistant Specialist, Extension Jean G. Wilson, B.A., Supervisory Assistant Keturah Reinbold, M.S., Research Assistant Jane Ashley, Technical Assistant Lowell Davis, Technical Assistant Nancy D. DeWitt, B.S., Technical Assistant Marcia Janes, B.S., Technical Assistant Lu-PiNG Kan, M.S., Technical Assistant Marie Monkman, M.S., Technical Assistant Stephen Roberts, B.S., Technical Assistant Douglas K. Sell, B.S., Technical Assistant Section of Faunistic Surveys and Insect Identification Philip W. Smith. Ph.D., Taxonomist and Head Wallace E. LaBerge. Ph.D., Taxonomist Milton W. Sanderson, Ph.D., Taxonomist Lewis J. Stannabd, Jr., Ph.D., Taxonomist Robert W. Poole, Ph.D., Assistant Taxonomist John D. Unzicker, Ph.D., Assistant Taxonomist Donald W. Webb, M.S., Assistant Taxonomist Bernice p. Sweeney, Junior Professional Scientist Section of Aquatic Biology George W. Bennett, Ph.D.. Aquatic Biologist and Head D. Homer Buck. Ph.D., Aquatic Biologist R. Weldon Larimore, Ph.D., Aquatic Biologist William C. Starrett. Ph.D., Aquatic Biologist Robert C. Hiltibran, Ph.D., Biochemist William F. Childers. Ph.D., Associate Aquatic Biologist Donald F. Hansen. Ph.D., Associate Aquatic Biolo- gist Richard J. Baur, M.S., Research Assistant Dennis L. Dooley, Technical Assistant Donald W. Dufford, M.S., Technical Assistant Mary Frances Martin, Technical Assistant Robert F. Randall. Ph.D., Technical Assistant C. Russell Rose. Field Assistant Warren U. Brigham. M.S., Junior Technical As- sistant Section of Botany and Plant Pathology J. Cedric Carter, Ph.D., Plant Pathologist and Head Robert A. Evers, Ph.D., Botanist Junius L. Forsberg, Ph.D., Plant Pathologist CONSULTANTS: Parasitology, Norman D. Levine. Ph.D., Professor of Veterinary Parisitology and Vetenriary Research. University of Illinois; Wildlife Research. Willard D. Klimstra. Ph.D., Professor of Zoology and Director of Cooperative Wildlife Research. Southern Illinois University; STATISTICS. HORACE W. Norton. Ph.D., Professor of Statistical Design and Analysis, University of Illinois; ENTOMOLOGY. GILBERT P. Waldbauer, Ph.D.. Associate Professor of Entomology. University of Illinois. Section of Wildlife Research Glen C. Sanderson, Ph.D., Wildlife Specialist and Head Frank C. Bellrose. B.S., Wildlife Specialist Richard R. Graber, Ph.D., Wildlife Specialist Harold C. Hanson, Ph.D.. Wildlife Specialist William L. Anderson, M.A., Associate Wildlife Specialist W. W. Cochran, Jr.. B.S., Associate Wildlife Specialist William R. Edwards, M.S., Associate Wildlife Specialist Jack A. Ellis. M.S., Associate Wildlife Specialist Ronald F. Labisky, Ph.D., Associate Wildlife Spe- cialist Charles M. Nixon, M.S., Associate Wildlife Special- Stanley L. Etteb, M.S., Assistant Wildlife Spe- cialist Robert E. Greenberg, M.S., Assistant Wildlife Spe- cialist G. Blair Joselyn. M.S., Assistant Wildlife Special- ist George B. Rose, Ph.D., Assistant Wildlife Specialist David R. Vance, M.S., Assistant Wildlife Specialist Ronald L. Westemeier. B.S., Assistant Wildlife Specialist Ronald E. Duzan, Technical Assistant Norma J. Hubbard. Technical Assistant Mary Ann Kjos, Technical Assistant Helen C. Schultz, M.S., Technical Assistant Hilda Wiesenmeyer. Technical Assistant Eleanore Wilson, Technical Assistant Robert D. Crompton, Field Assistant James W. Seets, Laboratory Assistant Section of Administrative Services Robert O. Watson, B.S., Administrator and Head Supporting Services WILMA G. Dillman. Property Control and Trust Robert O. Ellis, Assistant for Operations Lloyd E. Huffman, Stockroom Manager J. William Lusk, Mailing and Distribution Ser- Publicotions and Public Relations Owen F. Glissendorf. M.S., Technical Editor Robert M. Zewadski, M.S., Associate Technical Editor Shirley McClellan. Assistant Technical Editor Richard M. Sheets, Technical Illustrator Wilmer D. Zehr, Technical Photographer Technical Library Doris F. Dodds, B.A., M.S.L.S., Technical Librarian Jean Ickes, B.A., M.S.L.S.. Assistant Technical Libr CONTENTS Acknowledgments 268 The Illinois River 269 River Mile and Bank 271 Dams and Navigation Pools 271 Current Speed 271 Bottom Soils and Turbidity 272 Pollution and Water Chemistry 273 Fishes 275 Field Procedure 276 Crowfoot Bar 278 Dredge (Dip Net) 281 Wading 284 Old Shells 284 Commercial Shells 284 Laboratory Procedure 284 Live Mussell Shell Collections 284 Old Shell Collections 285 Museum Collections 285 Mussel Fauna of the Illinois River 286 Effects of Pollution 340 Upper River 342 Peoria Pool 346 Starved Rock Dam to Chillicothe 347 La Salle-Peru 349 Hennepin 350 Henry 350 Chillicothe 350 Peoria Lake 351 Foot of Peoria Lake to Peoria Dam 353 La Grange Pool 353 Peoria Dam to Havana 354 Below Havana to La Grange Dam 355 Alton Pool 355 Organochlorine Pesticides 357 Conservation and Management 358 Summary 362 Literature Cited 365 Appendix 368 Index 394 Color Plates, live mussels collected in 1966 survey following page 308 This paper is published by authority of the State of Illinois, IRS Ch. 127, Par. 58.12. It is a contribution from the Section of Aquatic Biology of the Illinois Natural History Survey. Dr. William C. Starrett is an Aquatic Biologist for the Survey. (24238—6,500—2-71) Fig. 1.—Sites on the Illinois River where attempts were made to collect live mussels in the 1966 sur / ?66 subfossil mussel collecting sites are not shown. A Survey of the Mussels (Unionacea) of the Illinois River: a Polluted Stream William C. Starrett EARLY IN THIS CENTURY Dan- glade (1914:8) considered the Il- linois River the most productive mus- sel stream per mile in this country. At that time mussel shells were in great demand for use in manufacturing but- tons. About 1910 more than 2,600 boats were engaged in mussel fishing on the Illinois River between Peru and Graf- ton, Illinois (Ibid.) (Fig. 1). The maxi- mum commercial shell yield from the Illinois River occurred in 1909 and amounted to thousands of tons of good button shells (Ibid.). Very few statis- tics are available specifically for the Il- linois River; however, to give some in- dication of the magnitude of the har- vest, one shell buyer informed Danglade (1914:16) that in 1911 he bought 600 tons of shells from just two landings in the vicinity of Peoria, Illinois. Before 1907 most of the mussel fish- ing on the Illinois River was done by pearl hunters (Danglade 1914:8 & 31).^ One pearl found in a mussel taken in 1911 from the Illinois River at Chil- licothe was valued at $3,000 (Danglade 1914:15). After 1906 mussels were tak- en from the Illinois River primarily for the sale of shells to button-shell buyers, and the pearls and slugs were of second- ary consideration. By 1911 mussels in certain parts of the Illinois River were beginning to be af- fected by pollution, siltation, and mus- sel fishing (Forbes & Richardson 1913; Danglade 1914:48). The adverse ef- fects of pollution on the fishes and wild- life of the Illinois River during the first half of this century have been discussed by Mills, Starrett, & Bellrose (1966). ' For further information on the pearl industry of the Illinois River and various parts of the world, see Vertrees' (1913) book Pearla and Pearling. After World War II the great increase in the use of plastics in button manufac- turing had a further serious effect on the few mussel fishermen remaining along the Illinois River. About 1962 a renewed interest in mus- sel fishing on Illinois streams was stimu- lated by the market demand for Illinois shells by the Japanese pearl-culture in- dustry. Earlier the Japanese had ob- tained most of their shells from the Tennessee River system, but due to the decline of this natural resource in those waters, the buyers had to look for new sources farther north. Pearl culturists have found that a calcareous nucleus inserted into the oys- ter (Pinctada) is the best material to use for a pearl to form around (Cahn 1949:48). According to Cahn (1949: 49) : "As nuclei range in diameter to a maximum of more than six milli- meters, the first requirement for their production is a heavy, solid shell. Most nuclei are prepared from the shells of fresh-water mol- lusks. Unfortunately for the in- dustry, Japan produces no bi-valve with a shell thick enough to produce nuclei of the larger diameters in quantities sufficient to supply the demand. Search for the desired ma- terial led to the United States where admirable shell material finally was found in enormous quantities in the Amhlema, Quadrula, Pleurobema, and Megalonais species from the Mississippi River and its major trib- utaries. All have massive shells and were found to yield a high propor- tion of satisfactory nuclei similar in hardness and specific gravity to the superimposed nacre." 267 268 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Lopinot (1967: 15) mentioned that shells produced in Red China also are suit- able for use as nuclei in pearl culture. As a result of the new Japanese mar- ket for shells from Illinois waters, the sales of Illinois mussel fishing licenses rose from 69 in 1961 to 1,279 in 1966 (Lopinot 1967:12 and pers. comm., 18 January 1968). From the larger Illi- nois streams the best grade of shells for use in pearl culture occurs in the Wa- bash River, the next in the Illinois River, and the third in the Mississippi River. The 1966 commercial mussel (shells) catch from the Illinois River as reported by the exporters was 1,118.40 tons val- ued at $109,460.83; for the entire state of Illinois it was 3,557.65 tons valued at $604,307.83 (Lopinot, pers. comm., 5 June 1967). Soon after the increase in mussel fish- ing in the early 1960's, Messrs. William J. Harth and Alvin C. Lopinot of the Illinois Department of Conservation and the author realized that no current in- formation was available concerning the state's mussel fauna and the new mus- sel fishery. The laws at that time on mussel fishing in Illinois were designed to cope with the old fishery involved in selling shells to the button manufac- turers rather than with the new Japanese market requiring large shells of a limited number of species. Studies of mussels were needed on the Wabash, Illinois, and Mississippi rivers. Indiana has since made studies of the mussels of the Wa- bash River, and these studies should be of benefit to Illinois (Bingham 1968; Meyer 1968). In 1966 Lopinot (1967) made a general study of the commercial aspects of the new mussel fisheries of the Wabash, Illinois, and Mississippi rivers. The author has been studying the biology and chemistry of the Illi- nois River and its bottomland lakes relative to pollution for a number of years. Since a considerable amount of old base-line data on the mussels of the Illinois River (Calkins 1874; Kelly 1899; Baker 1906; Forbes & Richardson 1913; Danglade 1914; and Richardson 1928) were available for comparisons with data on the present mussel fauna, the author was interested in expanding his studies to include an investigation of the mus- sels of that river. Additional funds were made available to him in 1966 and 1967 for such a study by the Bureau of Com- mercial Fisheries (U.S. Fish and Wild- life Service) and the Illinois Depart- ment of Conservation. The basic purposes of this investiga- tion were to make a survey of the pear- ly mussel (Mollusca: Pelecypoda: Un- ionacea) populations of the entire Illinois River in order to formulate a sound basis for managing the mussel resource of this river, and to determine what species and distributional changes had taken place during the past century. The manuscript was reviewed by Dr. David H. Stansbery of The Ohio State Museum and The Ohio State Univer- sity and was edited by Robert M. Zewad- ski of the Illinois Natural History Sur- vey. The first draft of the section in this paper titled "Mussel Fauna of the Illinois River" was read by Dr. Joseph P. E. Morrison of the U.S. National Museum, Dr. Paul W. Parmalee of the Illinois State Museum, and Dr. Henry van der Schalie of the University of Michigan Museum of Zoology. The project and this publication were financed by a grant-in-aid under P. L. 88-309 (Commercial Fisheries Research and Development Act) from the Bu- reau of Commercial Fisheries, by the Illinois Department of Conservation, and by the Illinois Natural History Survey. ACKNOWLEDGMENTS f I wish to thank Dr. David H. Stans- bery of The Ohio State Museum and The Ohio State University for his help in identifying many mussels (naiads) and his advice and suggestions in mat- ters pertaining to the taxonomy of mus- sels and to the manuscript. Before the ji project was started. Dr. Paul W. Parma- U lee of the Illinois State Museum kindly fi furnished me with a collection of identi- V fied mussel shells and records of his Illi- nois River collections, and made many suggestions on collecting mussels. Dr. ' Feb., 1971 Starrett: Mussels of the Illinois River 269 Joseph P. E. Morrison of the U.S. Na- tional Museum ^v•as very helpful in ad- vising me about the Illinois River shells deposited in the National Museum, fur- nishing me his personal collection data from the Illinois River, rendering an opinion on several specimens of Lamp- silis from the river, and giving many suggestions on the taxonomy of mussels. I appreciated receiving the museum rec- ords of Illinois River shells and the taxonomic suggestions given to me by Dr. Henry van der Schalie of the Uni- versity of Michigan Museum of Zoology. I am indebted to Dr. Donald F. Hoff- meister of the University of Illinois Mu- seum of Natural History and Dr. Alan Solem of the Field Museum of Natural History for the courtesies extended me when I visited their museums to ex- amine shells from the Illinois River. Ap- preciation is expressed to Dr. William J. Clench of the Museum of Compara- tive Zoology, Harvard University, for furnishing me with the records of Illi- nois River shells deposited in that mu- seum. I wish to thank Dr. Kenneth Boss, also of the Museum of Compara- tive Zoolog)', for sending four lots of Illinois River naiads contained in that museum's collections to Dr. David H. Stansbery for examination. I wish to express my appreciation to Mr. William J. Harth of the Illinois Department of Conservation for his in- terest in the study and for making it possible to obtain a grant from the Bu- reau of Commercial Fisheries. Mr. Al- vin C. Lopinot of the Illinois Depart- ment of Conservation helped me in many ways on the project and furnished some of the photographs used in this paper. I wish to thank Dr. George W. Bennett of the Illinois Natural History Survey for his many suggestions and for critical- ly reading the manuscript. The admin- istrative assistance received from Miss Maryfran Martin of the Illinois Natural History Survey and Mr. Leslie "Ed" Whitesel of the Bureau of Commercial Fisheries was greatly appreciated. I wish to express my appreciation for the excellent cooperation and help given me in the field and laboratory by the following employees: Messrs. Gerald Roat (temporary employee), Jerry Grif- fin (temporary employee), Mike Conk- lin (temporary employee), Jon Stelter (temporary employee), Webb Moss (temporary employee), and Dennis L. Dooley (Illinois Natural History Sur- vey). The color photographs used in the plates and certain other photographs contained in this paper were taken by Mr. Wilmer D. Zehr, Technical Photog- rapher of the Survey. The color plates were printed by the Edward Hine Com- pany, Peoria, Illinois. Mr. Richard M. Sheets, Technical Illustrator of the Sur- vey, made the map and graphs. For her painstaking assistance in locating hard-to-find references and procuring photocopies, I wish to thank Mrs. Doris F. Dodds, Survey Librarian. I am especially grateful to Mr. Rob- ert M. Zewadski, Associate Technical Editor of the Survey, for his patience and most helpful suggestions in the edit- ing of this report. I wish to thank Mr. Allan Poole of the Division of Sanitary Engineering of the Illinois Department of Public Health for furnishing the 1967 data on ammonia nitrogen (N) and total phos- phates (PO^) used in this paper. Mr. Edwin Fall, Greater Peoria Sanitary Dis- trict, kindly furnished information on the treatment of wastes in the Peoria area. Appreciation is expressed to Dr. Willis N. Bruce of the Illinois Natural History Survey for making the organochlorine pesticide determinations on some of the mussels collected in this investigation. THE ILLINOIS RIVER The Illinois River is formed by the confluence of the Kankakee and Des Plaines rivers southwest of Chicago (Fig. 1 ) . Since the completion of the Chicago Sanitary and Ship Canal in 1900 water has been diverted in varying amounts (maximum 10,000 cfs) from Lake Mich- igan at Chicago (including domestic and industrial water pumped from Lake Michigan and later dumped into the canal as treated and untreated wastes) 270 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 through the canal to the Des Plaines River at Lockport and thence into the Illinois River. The Illinois River prop- er (Fig. 2) is 272.9 miles in length and the entire waterway from Lake Michi- gan to the mouth of the Illinois River at Grafton (Mississippi River) is 327 miles. The river and its tributaries have a drainage basin of 32,081 square miles (Barrows 1910:1). The maximum dis- charge of the Illinois River at Kingston Mines (river mile 145.3) in the water year 1965-1966 was 51,700 cfs, the mean discharge was 16,188 cfs, and the mini- mum discharge was 3,990 cfs (United States Geological Survey 1967:132). "The Illinois Valley is naturally divided into an upper and a lower part. The upper Illinois, compris- ing the westward -flowing section from the junction of the Des Plaines and Kankakee to the great bend near Hennepin, is independent of preglacial drainage lines and is ex- cavating a new course, its bed be- ing usually on the rock. The lower Illinois, extending from the great bend to the mouth, occupies the pre- glacial channel, in which the rock bottom lies nearly 100 feet below the bed of the present stream. * * * "The old river channel of the low- er Illinois is much too large for the present volume of flow, so that it has been filled up by alluvial de- posits forming the present bottom lands. The deposition of material has also been aided by the flat slope of the stream, the fall in the lower 223 miles being only 33 feet" (Hos- kins, Ruchhoft, & Williams 1927:4- 5). Formerly, between La Salle and Graf- ton there were about 400,000 acres of bottomlands subject to overflow by the Illinois River. Some of these overflow lands were in permanent bottomland lakes connected with the river. During the first part of the century nearly 200,- 000 acres of these bottomlands and lakes were drained and leveed off from the river for agricultural purposes. One of these, Thompson Lake, near Havana in Fulton County, was drained in the ear- ly 1920's. The mollusca of this former bottomland lake were studied before 1900 by Strode (1891a and 18916). FiQ- 2.—The Illinois River below Pekin in the La Grange navigation pool at river mile 1 48.0. Photo by W. D. Zehr. Feb., 1971 Starrett: Mussels of the Illinois River 271 Presently about 8,000 acres of aban- doned drainage districts have been re- stored as bottomland lakes (type 58) (Hutchinson 1957:123-125). In the current study, mussel collections were made in two of these lakes, Lake Ma- tanzas and Meredosia Lake. The col- lecting site referred to as Quiver Lake, near Havana in Mason County, is mere- ly a large slough connected with the river. River Mile and Bank The Illinois River is a navigable stream, and the boat channel is well marked with buoys, lights, and markers. These navigational aids are located in detail in the U.S. .\rmy Engineer Dis- trict, Corps of Engineers, Chicago, Illi- nois, publication Charts of the Illinois Waterway from Mississippi River at Grafton, Illinois to Lake Michigan at Chicago and Calumet Harbors. In this paper references are made to river miles based on the Corps of Engineers' chart book of the Illinois Waterway. A river mile designation is the exact number of miles upstream from the mouth of the river at Grafton. The engineering designation of the sides of the river adjacent to the chan- nel is used here and is termed "bank." The bank side is the left bank (LB) or right bank (RB) as viewed from mid- stream by the observer facing down- stream. Dams and Navigation Pools "Before 1900, low dams were built at Marseilles, Henry, Copperas Creek, La Grange, and Kampsville. Because they were low, their great- est effect on the stream was during periods of low water" (Mills, Star- rett, & Bellrose 1966:5). In the 1930's higher dams with locks for navigation were constructed on the Illi- nois River to help maintain a 9-foot channel. These locks and dams were built at Dresden Island (24 feet at river mile 271.5), Marseilles (24 feet at river mile 247.0), Starved Rock (19 feet at river mile 231.0), Peoria (11 feet at river mile 157.6), and La Grange (10 feet at river mile 80.2). The lower part of the river is under the influence of the Alton dam on the Mississippi River ( Fig. 1 ) . The waters impounded by these dams are called navigation pools, and throughout this paper refer- ences are made to these pools as the geographic locations of the various sec- tions of the river. The lower section of the river is the Alton pool (river miles 0.0-80.2) ; the La Grange pool is between the La Grange dam and the Peoria dam (river miles 80.2-157.6) ; the Peoria pool is between the Peoria dam and the Starved Rock dam (river miles 157.6-231.0); the Starved "Rock pool is between the Starved Rock dam and the Marseilles dam (river miles 231.0-247.0) ; the Marseilles pool is be- tween the Marseilles dam and the Dres- den Island dam (river miles 247.0- 271.5) ; and the Dresden pool of the Illinois River covers only the lower 1.4 miles of this pool impounded by the Dres- den Island dam (river miles 271.5- 272.4) ; the remaining upper part of this pool is the Des Plaines River. Current Speed "The fall in the Illinois River is but slight—an average of .267 of a foot per mile of its total length. Fif- ty and seven tenths feet of this fall occur in the first forty-two miles of its course, and from Utica to the mouth of the river the total fall is but 31 feet, or an average of .137 of a foot to the mile. The effect of this slight fall is seen in the slug- gish current of the Illinois, which ranges from .4 of a mile per hour at the lowest water to 1.737 miles when at twelve feet above low- water mark. The usual rate of flow for ordinary stages varies, however, from l'/4 to 2/2 miles per hour" (Forbes & Richardson 1920 :xl- xli). These records of current speeds were made before 1908. Observations made in the present study reveal that the river is now more sluggish than it was 272 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 in the early part of this century. At ordinary river stages the current speed now is only about 0.6 mile per hour. The increase in sluggishness of the river is believed by the author to be a result of the higher dams now on the river and the reduction in diversion of water from Lake Michigan. In the Alton and La Grange pools ( 1966) the current ranged from 0.5 to 1.1 miles per hour. During low river stages the current is sometimes not per- ceptible in the midpart of the La Grange pool (river mile 113.1). In the extreme lower part of the Peoria pool the river is rather narrow (river miles 157.6-162.8) and the current here in 1966 ranged from 0.4 to 1.1 miles per hour. Be- tween river miles 162.8 and 179.2 the river is 1-2 miles in width and is re- ferred to as Peoria Lake (Lower, Middle, and Upper Peoria lakes) . No current was perceptible in Peoria Lake except at the narrow part of the river connect- ing Lower and Middle Peoria lakes ("Narrows" at river mile 166.7) where the current was 0.9 mile per hour. In the remainder of the Peoria pool (river miles 179.2-231.0) the river is typical of much of the stream, and the current here ranged from 0.2 to 0.6 mile per hour. Single current determinations were made in 1964 by the author in Starved Rock pool (0.6 mile per hour) and in the Marseilles pool (0.8 mile per hour) . Bottom Soik and Turbidity Because of the heavy towboat traffic and dredging in the navigation channel, mussel fishing is largely confined to the waters adjacent to the channel. There- fore, we are particularly concerned with the bottom substrates lying between the navigation channel and the shoreline. "Soil pollution has been present in Illinois River waters since the recession of the last ice sheet. How- ever, the laying bare of the soil in agricultural operations has greatly increased the problem" (Mills, Star- rett, & Bellrose 1966:5). In Illinois the sedimentation problem re- sulting from farming operations increased tremendously in the middle 1930's, as revealed by studies made by Brown, Stall, & De Turk (1947) and the author's personal observations on the Illinois River. This problem came about through the increase in the planting of row crops, particularly soybeans, and the advent of heavy, powered farm equipment. Ac- cording to the Illinois Cooperative Crop Reporting Service (1965: 58-59), coun- ties in Illinois partly or wholly drained by the Illinois River in 1964 had 6,220,200 acres planted to corn and 3,466,100 acres in soybeans. In other words, in 1964 about 47 percent of the watershed of the Illinois River in Illinois was in row crops. In 1966, 62 percent of private cropland in this country needed conservation treat- ment (Stall 1966:80). The increase in the sluggishness of the river, as mentioned above, and the in- creased planting of row crops on the watershed have, in the author's opinion, made siltation in the past 30 years an important factor adversely affecting the survival of mussels and other organisms in the Illinois River and its bottomland lakes (river miles 0.0-231.0). A study made in 1950 on Lake Chautauqua, an Illinois River bottomland lake near Ha- vana, revealed that sediment deposits had reduced the storage capacity of the lake by 18.3 percent in 23.8 years (Stall & Melsted 1951:1). "The sediments in Lake Chau- tauqua are mostly of a fine texture and form a loose, flocculent 'false bottom' (not similar to the type found in bog lakes) over the original lake bottom. A slight disturbance of the 'false bottom' causes particles to become resuspended and so increases the turbidity of the water" (Jackson & Starrett 1959:160). The bottom of the river in the Alton, La Grange, and Peoria pools was chiefly hard mud overlaid in numerous areas with fine sediment deposits (soft-mud bottom) similar to the "false bottom" found in Lake Chautauqua. In some sections of the upper La Grange and Peoria pools the silt contained a mixture Feb., 1971 Starrett: Mussels of the Illinois River 273 of fine sand particles. Very few clean sand or gravel bottoms were observed in the lower three navigation pools. As mentioned earlier, the bottom in the upper two pools (Starved Rock and Marseilles) was primarily rock. In some parts of these two pools the rock was overlaid with mud, sand, and/or gravel. Turbidity readings (midchannel) made during minimum flow periods by the author are summarized in Table 1. The high turbidities observed in the lower two pools tended to reflect the silted conditions (soft-mud bottom) of the lower river and heavy silt loads brought into this section of the river by the tributary streams. On June 24, 1964, following a flash flood, the Illinois Sani- tary Water Board determined the tur- bidity in one part of the Alton pool to be 2.000 turbidity units. The author has made numerous ob- servations on the effect a towboat has on turbidity in the various parts of the river. A towboat underway causes a strong current and washing action on the silt bottom ("false bottom") inshore, which resuspends the silt particles, there- by increasing the turbidity. The increase in turbidity is more noticeable in the lower three pools, particularly in the Alton pool, than it is upstream because of diff'erences in bottom types as discussed above. The outrush of the water from shore toward the channel caused by a towboat also temporarily exposes the shallow areas. On November 18, 1964, in the Alton pool at river mile 65.1, the Table 1.—Ranges of turbidity (Jackson tur- bidimeter! during minimum flow periods in the navigation pools of the Illinois River (1963 through 1966) Navigation 274 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Horning 1965) . Moreover, the other cities within the Illinois River basin ha\e grown, and make their increas- ing demands on and contributions to the stream" (Mills, Starrett, & Bellrose 1966:4-5). By 1911 the upper section of the Illinois River (Marseilles and Starved Rock pools and the upper section of the Peoria pool) was heavily polluted by untreated domes- tic and industrial wastes from the Chicago area (Forbes & Richardson 1913) . During and immediately following World War I, pollution became even more severe and critically affected the river down- stream as far as Peoria (Pu^dy 1930:10; Richardson 1928). In the past 40 years conditions in the upper section of the river (Marseilles and Starved Rock pools) and Peoria Lake have improved as the result of the treat- ment of wastes, reduction of flow, and augmentation of pollution laws. In 1922 the population equivalent of domestic and industrial wastes emptied into the river was 6,211,471 (Hoskins, Ruchhoft, & Williams 1927:25), but by 1960 it had dropped to an equivalent of 2,417,000 people (United States Public Health Service 1963 : III-l ) . However, the bene- ficial gains in pollution abatement during the past 40 years, reflected by the re- duction in BOD (Biochemical Oxygen Demand, Table A-P) , that have occurred in spite of increases in human populations and industry on the watershed tend to be offset to a serious degree by the high concentration of ammonia nitrogen originating from treated and untreated effluents and possibly from agricultural fertilizers. In 1967 maximum determina- tions of ammonia nitrogen (N) ranged from 0.9 ppm in the lower river to 8.2 ppm in the upper Illinois River (Allan Poole, pers. comm., 11 March 1968). At river mile 274.0 in the Des Plaines River in 1967 the maximum determina- tion of ammonia nitrogen was 26.0 ppm (Ibid.). Dissolved oxygen now is considerably higher in the upper river and Peoria ' The letter A designates that a table Appendix of this paper. Lake than it was in the 191 1-1928 period (Mills, Starrett, & Bellrose 1966:9). However, during the past 50 years the dissolved oxygen content of the river below the Peoria-Pekin metropolitan area has decreased. Also the dissolved o.xygen content in part of the Peoria pool above Middle Peoria Lake is still critical. The midsummer dissolved oxygen determi- nations made by the author (Table A-2) and the chemical, radiological, and bac- teriological determinations of the Illinois Sanitary Water Board (1967) presented in Table A-1 reflect the pollutional condi- tions of the river in 1966. The bacterial counts indicate pollution in the entire river in 1966. The dissolved oxygen was usually rela- tively high in the upper parts of the navi- gation pools below the dams, and in mid- summer it decreased downstream within the pools (Table A-2). In several of the pools, especially the Alton pool, where the reoxygenated water is subjected to very few additional domestic and industrial wastes, the dissolved oxygen would be expected to remain relatively high rather than to decline as shown in Table A-2. The continual decline in dissolved oxygen in these pools accompanied with a de- crease in BOD is probably related to nitrification oxidation, as was demon- strated by the United States Public Health Service (1963:IX-21) in July of 1962. In the early 1960's the United States Public Health Service (1963:V-26) de- termined these amounts of toxic metals in the Illinois River: (i) copper was less than 0.30 ppm; (ii) nickel ranged from 0.01 ppm to 0.25 ppm; (iii) zinc was as high as 0.13 ppm; and (iv) chromium varied from 0.01 ppm to 0.08 ppm. Relative to detergents, Sullivan & Evans (1968:198-199) reported that in the Illinois River at Peoria (1.4 miles upstream from the outfall of the Greater Peoria Sanitary District treatment plant) the mean MBAS (methylene blue active substance) dropped from 15.7 tons per day in the 1959-1960 period to 9.0 tons per day in the 1965-1966 period as a re- sult of the conversion from ABS deter- gents to the more readily biodegradable Feb., 1971 Starrett; Mussels of the Illinois River 275 LAS compounds. The author's 1966 ABS determinations from the Illinois River were about one-half of the amounts of his earlier determinations (Table A-2) . According to Verduin (1967:167- 168) : "The three important sources of phosphorus contribution to our waters are organic matter in sewage, phosphorus-containing detergtents, and phosphorus in the runoff and drainage from farmlands, most of which receive heavy applications of phosphate fertilizers." Mr. Allan Poole (pers. comm., 11 March 1968) informed the author that in 1967 total phosphates (PO4) were as high as 8.3 ppm in the Marseilles pool and 5.7 ppm at Peoria. Sullivan & Hullinger (1969:216) in 1967 determined the mean total phosphorus concentration in Upper and Middle Peoria lakes to be 1.13 ppm, of which orthophosphates represented 75 percent of the total phosphorus; 64 per- cent of the total phosphorus was in a dissolved state. These authors (1969:215) mentioned that concentrations of total phosphorus in Peoria Lake were 17 to 94 times higher than those found in other bodies of water, according to the litera- ture they reviewed. In the author's opinion treated sewage and industrial effluents (including detergents) were the main sources of phosphorus in the Illinois River. Even though the Illinois River was extremely rich in nutrients, algal blooms in the mainstream were limited by high turbidities and possibly by syner- gistic effects of toxic metals. When mak- ing dissolved oxygen and pH determina- tions on sunny days, the author found that primary production was quite limited in the mainstream of some parts of the river. Biological data collected from the Illi- nois River by the author and his associates have revealed pollutional aspects not dis- closed by chemical and bacteriological data (Mills, Starrett, & Bellrose 1966). These pollutional aspects with their effects on the mussels are discussed later in this paper. Fishes Mention of the fishes of the Illinois River is included here because of the fishes' role as hosts for the parasitic, or glochidium, stage of freshwater mussels. Fig. 3.—An Illinois Natural History Survey crew electrofishing in the La Grange navigation pool of the Illinois River. Photo by Dr. George W. Bennett. 276 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Certain species of mussels require a spe- cific host fish for a short period of time, whereas other species are evidently able to use several kinds of fishes as hosts (Baker 1928:13). Many changes have occurred in the fish fauna of the river since 1907 and will be discussed in detail in a later paper by Starrett & Smith. Since 1950 the author has been studying the fishes of the Illinois River and its bottomland lakes (Starrett & Fritz 1965) . In this period 101 species of fishes have been collected from the river and its bottomland lakes by the author (Fig. 3) . FIELD PROCEDURE The mussel sur\'ey of the Illinois River was conducted from June 9 to October 28, 1966. Most of the collecting was done during the first 3 months of the program. A total of 429 collections was made for live mussels. The collections were made with an exploratory type of crowfoot bar (brail) and a mussel dredge and by wading (hand collecting) between river miles 0.9 and 272.0 (Table 2) . In these collections 4,247 mussels were taken alive (Table A-3). An additional 20 live mussels were picked up by hand in the Aux Sable River near its mouth at Illinois River mile 268.2 in the Marseilles navigation pool. The shells of all of the live mussels collected in the survey were saved and taken back to the field laboratory of the Illinois Natural History Survey near Havana, Illinois, for identifi- cation and storage. (Several live mussels were obtained from commercial mussel fishermen operating in the Peoria pool in 1969, and the records of these shells are included in this paper.) Upon the completion of a collection, the live mussels were placed in a gunny sack with a tag bearing the collection number. At the end of a day's collecting each collection of live mussels was weighed and steamed. The live mussels were weighed on a Chatillon scale to the nearest 0.01 pound. Each collection of mussels was placed in a steel canner for steaming; a portable two-burner Cole- man stove was used in the field as the heat source. After the mussels of an individual collection were steamed, the shells were cleaned and a rubber band was tightly secured around each pair of valves. The cleaned shells of a col- lection were resacked for storage. The meats and the bottom of the canner were examined for pearls.^ A few live mussels from several parts of the river were cleaned with a knife and the fresh meats were wrapped in foil and frozen. Later these meats were checked by the electron capture gas chromatography method for the presence of organochlorine pesticides by Dr. W. N. Bruce of the Illinois Natural History Survey. A 16-foot, square bow Arkansas Travel- ler boat powered by a 9/2 -horsepower outboard motor was used in making the crowfoot bar and mussel dredge collec- tions of live mussels. The speed of the boat was adjusted to compensate for current speed variations in order to fish the mussel collecting devices at a uni- form speed. A wooden stanchion was mounted near the bow of the boat and was used for securing the dredge boom and the crowfoot bar line. A professional mussel fisherman was employed during the first 2 weeks of the program to serve in an advisory capacity to assure proper operation of the collecting devices. The survey was designed to sample, on a stratified basis, as many different sites in the entire length of the river as was possible with one boat crew in a 3-month period (Table 2). The sam- pling sites included known former and existing mussel beds as well as other areas. Former mussel beds were located from reference points given in the litera- ture (Danglade 1914; Forbes & Richard- son 1913; and Richardson 1928), inter- views with elderly commercial fishermen, and concentrations of old shells along the shoreline. Since 1964 the author had noted the areas where most of the commercial mussel fishing was being conducted. Those observations, coupled ^ None of the few dozen small pearls and slugs found durinj? the 1966 survey was of any commer- cial value. Feb., 1971 Starrett: Mussels of the Illinois River 277 with interviews with active commercial musel fishermen, enabled us to locate the known productive mussel beds. The stratified basis of sampling was extended to the remainder of the river by attempting to select as collecting sites those habitats appearing to be the best for mussels. In conducting fish surveys with limited personnel and time on a large river like the Illinois, the author has found that the stratified, or selective, habitat sampling method gives Table 2.— Illinois River locations by mile numbers" and bottomland lakes where mussel collecting was done in the 1 966 survey. 278 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 the investigator more assurance of col- lecting a variety of species in a given locality than by sampling at random. The author believes that a combined series of such collections permits one to use the data with some confidence for comparative purposes with sample series from other parts of the river. For ex- ample, in the more polluted navigation pools of the Illinois River the author electrofishes (Fig. 3), on a unit-of-time basis, habitats that he believes should support various species of sunfishes (Centrarchidae) as well as other fishes. He usually takes only a few or none of the more desirable species, whereas in similar habitats of other navigation pools such species may occur abundantly. Such results clearly reflect the effects of pollu- tion on fish life and show the cumulative effects of poor water quality on a stream's ecosystem, which may not be discernible through chemical and bacteriological analyses of the water. The author merely incorporated his fishing sampling tech- niques into the design of the 1966 mussel survey to determine the effects man has had upon the mussel fauna of the river. Furthermore, this sampling design fitted well into the management aspects of the survey, which were to determine the con- dition of known mussel beds and to lo- cate new beds that might be of commer- cial importance. Crowfoot Bar Since 1897 (Smith 1899:294) the crowfoot bar, or brail, has been used widely in the Midwest as a commercial fishing device to collect mussels (Fig. 4) . The commercial bar varies from 10 to 17 feet in length and may have as many as 200 hooks, or crowfeet (4-pronged hooks), attached to the bar by short lines or chains. After conversing with several commercial fishermen, the author decided to use a bar much shorter than the commercial bar. The short bar was easier to fish and enabled us to cover greater distances in less time than would have been possible using a commercial bar. Also, the short bar was quite ver- satile in fishing stumpy and narrow habitats. The short bar used in this study was the exploratory crowfoot bar designed by the Tennessee Shell Company for their fishermen to use in locating new fishing sites in the Midwest. Three Fig. 4.—Typical crowfoot bar used by commercial mussel fishermen on the In 1 966. Photo by Alvin C. Lopinot. linois River Feb., 1971 Starrett: Mussels of the Illinois River 279 of these bars were built for us by the Tennessee Shell Company. The bar was 61.25 inches long, and 44 hooks (0.1 inch in diameter) were suspended from the bar (Fig. 5). A nylon towline was secured to either end of the bar, and the bar was fished from the bow of the boat. The boat was run in reverse, and all of the crow- foot bar fishing was done in a down- stream direction. The bowman handled the bar and signaled the boat operator when the towline was played out and the bar commenced to fish. Upon noting this signal, the boat operator began tim- ing the fishing with a stop watch. He also recorded on the field sheet the river depths and bottom types observed by the bowman while the bar was fish- ing (Table 3). The depths were taken Fig. 5. — The exploratory crowfoot bar used on the Illinois River in the 1966 mussel survey. Photo by W. D. Zehr. 280 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Table 3.—Average depths and depth ranges at which mussel collections were made with the crowfoot bar and dredge in the Illinois River in the 1966 survey. Feb., 1971 Starrett: Mussels of the Illinois River 281 survey and were not included in this paper. Since all of the 322 regular crowfoot bar collections were made on a timed basis, the author combined collections from individual sections or navigation pools and expressed the catches as num- bers of live mussels caught per 5 minutes of fishing (Tables 4 and A-4—A-8) . Dredge (Dip Net) According to Danglade ( 1914: 29-30) : "Since the time that the mussel fishery began on this river [Illinois], it was known that Peoria Lake con- tained large beds of good commercial shells, but until 1911 no very suc- cessful method of taking them had been devised, scissor forks, oyster tongs, rakes, and the ordinary mussel bar with crow-foot hooks proving unsatisfactory. The dip net was in- troduced during the spring of that year and is now used there almost exclusively, as it is simple in con- struction, inexpensive, and especially suited to soft mud bottoms free from logs and hang-ups, and where there is but little or no current. * * * In a general way the dip net con- sists of a heavy, fiattish iron hoop Fig. 6.—Sketch of a dredge fishing for mussels on the bottom of a river (from Danglade 1914:30). 282 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 of one piece, bent somewhat tri- angular in form, with two of its sides curved outward and fastened firmly with bolts to a pole or handle 16 to 20 feet long. The third side or bottom is straight and from 18 to 36 inches in length, and is usually provided with coarse teeth along its edge, which is bent downward. A net of 2-inch mesh, made of small chain or no. 96 trot line with a ca- pacity of a bushel or more, is fasten- ed to the hoop by means of chain links and trails behind it. A short Fig. 7,—The dredge used in the Illinois River in the 1966 mussel survey. Photo by W. D. Zehr. i Feb., 1971 Starrett: Mussels of the Illinois River 283 rope or bridle attached to the two curv^ed sides of the hoop leads to a single rope secured to the bow of the boat. When the water is rather deep, the boats are fitted with a boom pole extending forward from the bow, and the rope from the bridle is fastened to its end, thus giving greater length of rope and conven- ience of manipulation. Driven by a gasoline engine of from 4 to 20 horsepower, according to the size and weight of the dip net, the boat draws the apparatus through the water along the bottom" (Fig. 6). The dip net, or dredge as it is now called by local fishermen, is still an important commercial mussel fishing de- vice on the Illinois River. The dredge used in the 1966 survey (Fig. 7) was constructed by the Tennessee Shell Com- pany. It was 14.75 inches wide and was attached to a pole 15.0 feet long. The pole was marked off in feet to enable the dredge operator to make water depth readings while fishing (Table 3) . Our dredge was fished as described by Dan- glade by connecting the bridle of the dredge with a line to a wooden boom temporarily mounted on the bow of the boat (Fig. 8 and Tables A-4-A-8) . The author considered this method of fishing very effective over the predominantly mud or mud-sand bottoms of the lower three navigation pools of the river. The bottom types of the upper river were not suitable for using the dredge. In the survey 885 live mussels were taken in 74 dredge collections. In mak- ing these collections it was found that the dredge could be fished for only a very short distance or length of time (usually less than 1 minute) before it was necessary to raise it and clean out the net. This task was time consuming, since the entire net load of debris and dead shells had to be sorted through for live mussels before the collecting could be continued. This shortcoming of the dredge limited its use for us as an exploratory fishing device. Conse- quently, only 17 exploratory collections were made with the dredge and these were confined mainly to parts of Peoria Lake where, because of the almost non- existent current, it was impractical to Fig. 8.—Lowering the dredge Into the Illinois River during the 1966 mussel survey. Note the temporarily mounted boom on the bow of the boat to which the brail line was secured. From a color photo by the author. 284 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 fish the crowfoot bar. The average water depth fished in the dredge exploratory collections was 5.4 feet (range, 1.5-12.0 feet) . The dredge was used primarily for taking 57 quantitative samples of live mussels in the 400-foot marked sampling areas described above. In these collec- tions the dredging was done on the side of the river opposite the 400-foot line fished with the crowfoot bar. The dredge appeared to be efficient in taking most of the live mussels in its path other than specimens less than 1.5 inches long and the mud - burrowing slough sand - shell [Lanipsilis anodontoides f. jallaciosa) . The average depth fished in the quantita- tive collections with the dredge was 9.8 feet (range, 5.0-14.0 feet). Wading Early in the program Dr. Paul W. Parmalee suggested that crowfoot and dredge collections should be supple- mented with a series of wading collections to take small-sized mussels and species inhabiting shallow waters. During the survey 33 different sites were sampled on a time basis by one to five men (usually three) wading in the river and grubbing the bottom with their hands for live mussels (Tables A-4— A-8). The water depths in the wading collections varied from 0.0 feet to 4.0 feet. In these collections 1,123 live mussels were taken. Old Shells Upon the suggestion of Dr. David H. Stansbery we collected old shells (sub- fossil) from 21 different locations along the river (Table 2). The purpose of these collections was to obtain specimens for verification of old records in the literature and information on the distri- bution of species formerly present in the river. Commercial Shells In the fall of 1966 commercial piles of mussel shells were examined at Mere- dosia and Kampsville along the Illinois River and at Mt. Carmel, Illinois, along the Wabash River. The shells were selected at random from sorted and culled commercial piles. In this phase of the study 1,937 shells were identified and measured (height to the nearest 0.1 inch) in the field and returned to the piles. LABORATORY PROCEDURE Live Mussel Shell Collections Each field collection of shells was processed separately in the laboratory. The shells in each collection were identi- fied, numbered, weighed, and measured; their ages were determined; and they were stored temporarily in plastic bags. Tentative identifications of the shells were made by the author when each collection was sorted in the laboratory. Later, specimens representing each spe- cies taken in the survey together \vith complete series of certain species were submitted to Dr. David H. Stansbery for identification. As a result, most of the scientific names used here follow the nomenclature suggested by Stansbery (1961, 1962, and 1967). The nomen- clature involving the various species known from the Illinois River is dis- cussed in the next section of this paper. The English system of weights and measurements was used by the author in this study because an important phase of the investigation dealt with the com- mercial and management aspects of the river's mussel fishery. Ho\vever, metric system measurements made by Dr. Stans- ber\' relati\e to the taxonomy of several species are included. The shells in a collection were weighed individually by species on a Chatillon scale (0.01 pound). Shell length and height measurements were made with a Helios dial caliper (0.01 inch). These measurements were made in accordance with Stansbery's definitions (1961:10) : "LENGTH is the maximum an- tero-posterior dimension of the shell. "HEIGHT is the maximum dorso- ventral dimension of the shell meas- Feb., 1971 Starrett: Mussels of the Illinois River 285 ured at right angles to the length. This dimension docs not include the ligament, umbones nor the wing in the alate species, Proptera alata (Say) and Leptodea fragilis (Ra- finesque) ." Ages of the mussels were determined by counting the number of annuli on the shells (Stansbery 1961:12-13). Usually both shells of a pair were used in making an age determination over a transmitted-light chamber. In some instances it was quite difficult to dis- tinguish the true annuli from the false. However, the author believed that even though errors probably were made, the o\erall average age data for the more abundant species were accurate enough to be of value. Specimens representing all of the spe- cies taken in the survey were deposited in The Ohio State Museum at Colum- bus, Ohio. Series of specimens of the more common species were deposited in the Field Museum of Natural History at Chicago, Illinois. The catalog num- bers (OSM and FMNH) of these speci- mens have been listed for each species in the ne.xt section of this paper under the heading "Live Mussel Records (1966 Survey)." The remaining speci- mens were stored temporarily at the field laboratory of the Illinois Natural His- tory Survey near Havana. Estimated standing crops in pounds of live mussels and pounds of commercial shells per acre were calculated from the quantitative dredge collections: 1) Dredge width (1.23 feet) times the distance covered by the dredge in a collection (400 feet) equals the square feet sampled: 1.23 X 400 = 492 number of square feet sampled 2) Square feet in an acre (43,560) di- vided by the number of square feet sampled in a collection equals the portion of an acre sampled: 43,560 ^ 492 = 88.54 portion of an acre sampled 3) Live weight or commercial shell weight times the portion of an acre sampled equals the estimated stand- ing crop in pounds per acre. For example, a) 16.72 pounds equals the live weight of mussels taken in a dredge collection at river mile 1.0 b) 16.72 X 88.54 = 1,480.39, or 1,480 pounds estimated standing crop of live mussels in pounds per acre. Old Shell Collections The shells taken in the 1966 "bone" (subfossil) collections were identified by Dr. David H. Stansbery. The river mile numbers \vhere old shells were collected and museum catalog numbers of the specimens deposited in The Ohio State Museum are included in the next sec- tion of this paper for each species un- der the heading "Old Shell Records (1966 Survey)." Museum Collections The author attempted to verify pub- lished records of those species previous- ly reported from the Illinois River which were not taken in the 1966 live mussel and old shell collections. Verifications were made by curators at museums or by the author. Dr. Paul W. Parmalee (pers. comm., 21 November 1966) furnished the au- thor with copies of the accession pages of the Illinois State Museum at Spring- field, Illinois, including mussels Dr. Parmalee had collected from the Illi- nois River in the 1950's. Dr. Henry van der Schalie (pers. comm., 31 August 1967) sent the author information rela- tive to mussel shells from the Illinois River contained in the collections of the University of Michigan Museum of Zo- ology at Ann Arbor, Michigan. Dr. Joseph P. E. Morrison (pers. comm., 14 July 1967; 27 November 1967; 4 January 1968; 4 June 1968) provided records of mussels he collected from the 286 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Illinois River in 1924 and the 1930's. He also provided information concerning mussels taken from the river by the U.S. Bureau of Fisheries from 1907 to 1916 and by others and now deposited at the U.S. National Museum at Washington, D.C. Dr. William J. Clench (pers. comm., 12 August 1969; 25 November 1969) furnished the author records of the Illinois River mussel shells in the collections of the Museum of Compara- tive Zoology, Harvard University, Cam- bridge, Massachusetts. Several of the shells in this collection were examined for the author by Dr. David H. Stans- bery (pers. comm., 20 January 1970; 13 February 1970). Dr. Stansbery sent the author a list of the Illinois River naiads contained in the collections of The Ohio State Museum at Columbus, Ohio (pers. comm., 22 December 1969). Dr. Lowell Getz, while at the Uni- versity of Connecticut (now at the Uni- versity of Illinois), presented the author with some of the shells contained in the Benjamin Koons collection from the Illi- nois River in the 1870's. The author gave several of these shells to Dr. Paul W. Parmalee for deposit in the Illinois State Museum. The remainder of these shells will be presented to the Illinois Natural History Survey at Urbana, Illi- nois, and The Ohio State Museum. The author examined mussels from the Illinois River in the collections of the following museums: Field Museum of Natural History at Chicago, Illinois; University of Illinois Museum of Natural History (Frank C. Baker collection) at Urbana, Illinois; and Illinois Natural History Survey at Urbana, Illinois. Abbreviations of the names of the mu- seum and personal collections consulted during the preparation of this paper are: Benjamin Koons collection (BK), Field Museum of Natural History (FMNH), Illinois Natural History Survey (INHS), Illinois State Museum (ISM), Museum of Comparative Zoology (MCZ), The Ohio State Museum (OSM), U.S. Na- tional Museum (USNM), University of Illinois Museum of Natural History (UIMNH), and University of Michi- gan Museum of Zoology (UMMZ). MUSSEL FAUNA OF THE ILLINOIS RIVER This section deals with the past and present mussel fauna of the river. Through the years various generic and specific names have been used by dif- ferent authors for a number of the mus- sel species found in the Illinois River. Differences in opinions among taxono- mists concerning the nomenclature of many of these species still exist and will probably continue to exist until the evi- dence for solving the many problems is obtained. In this paper the author was more concerned with presenting a synop- tic report of the mussel fauna of the river which might be intelligible to cur- rent and future \vorkers than with the problems of taxonomy and nomencla- ture. Persons desiring to identify mussels from the Illinois River will find Parma- lee's (1967) booklet on the mussels of Illinois very helpful. To aid such per- sons the author has included with the synonymies of most of the species listed below pertinent references to Parmalee's publication and the scientific names used by him. Otherwise, the synonymies in- _ elude only those names referring to lUi- nois River records appearing in the lit- erature and personal communications and those found on museum specimens. For the benefit of those having a seri- ous interest in the Illinois mussel fauna the author has included at the end of the discussion of each species three cate- gories of mussels collected from the Illi- nois River: (i) "Museum Records," specimens not collected in the 1966 sur- vey; (ii) "Live Mussel Records (1966 Survey)," the Illinois River mile num- ber and river bank and/or the name of the bottomland lake where living speci- mens were collected in 1966 and their museum catalog numbers (mussels col- lected alive from the Peoria pool in 1969 were included here and designated as 1969 records) ; and (iii) "Old Shell Feb., 1971 Starrett: Mussels of the Illinois River 287 Table 5.—Mussel fauna of the Illinois River and its bottomland lakes in the period, 1906-1912 period, and 1966-1969 period." 870-1900 Kind of Mussel 1870- 288 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Records (1966 Survey)," the Illinois River mile where subfossil shells of the species were collected in 1966 and their museum catalog numbers. Phylum MOLLUSCA Class PELECYPODA Order EULAMELLIBRANCHIA Superfamily UNIONACEA Family MARGARITIFERIDAE Ortmann, 1911 Margaritifera margaritifera (Linnaeus, 1758) Margaritana margaritifera Linne: Baker (1906176) Baker (1906:76) reported that Cal- kins collected this species in the Illinois River. The author was unable to lo- cate a specimen of this species from the Illinois River in the museums he visited or contacted during this study. This species apparently is restricted largely to soft waters and is usually found in cold, clear, rather rapidly flowing small to medium-sized streams (Ortmann 1919:5; Clarke & Berg 1959:18). Ac- cording to Clarke & Berg (1959: 17) this species has not been collected from cen- tral North America. The Illinois River is a large, sluggish, hard-water stream located virtually in the heart of central North America. On the basis of this evidence the au- thor concluded that Baker's reporting of M. margaritifera in the Illinois River was an error and that this species should not be included in the mussel fauna list of the river presented in Table 5. Museum Records.—None. Live Mussel Records ( 1966 Survey). — None. Old Shell Records (1966 Survey).— None. Spectacle-Case Cumberlandia monodonta (Say, 1829) Cumberlandia monodonta (Say) : Parmalee (1967:25) Margaritana monodonta Say (=soleniformis Lea) : Baker (1906:76) Margaritana monodonta (Say) : Danglade (1914:10) The spectacle-case was listed by Baker (1906:76) as having been taken at Ha- vana, Illinois, by State Laboratory per- sonnel. Also Danglade (1914:42) men- tioned that he saw several specimens of this species from the Illinois River at the biological laboratory at Havana. A single specimen of the spectacle-case was collected in 1912 by Danglade (Ibid.) from the river at Diamond Island (ap- proximate river mile 24.5) above Har- din. Dr. Joseph P. E. Morrison (pers. comm., 14 July 1967; 27 November 1967) confirmed this record (USNM). Danglade (1914:42) reported that the spectacle-case was a rare species in the Illinois River in 1912. This species was probably similarly scarce in the Missis- sippi River where the van der Schalies (1950:456) listed the spectacle-case as occurring so rarely in the mainstream that collecting a specimen was merely a matter of chance. Neither a living nor a subfossil spec- tacle-case was taken in the 1966 survey. Nor was this species collected by Parma- lee (pers. comm., 29 June 1967) during the 1950's from the Illinois River. It appears that the spectacle-case has dis- appeared from the river in the past 50 years. Stansbery (1966:29) reported a similar disappearance of this species from the Ohio River. Museum Records.-—Above Hardin, Diamond Island (1912 Danglade) USNM 678486. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. Family UNIONIDAE (Fleming, 1828) Ortmann, 1911 Subfamily UNIONINAE (Swainson, 1840) Ortmann, 1910 Ebony Shell Fusconaia ebena (Lea, 1831) (Plate 3-18) Fusconaia ebenus (Lea) : Parmalee (1967:31; 1962:9) Feb., 1971 Starrett: Mussels of the Illinois River 289 Uniu ebenus Lea: Calkins (1874:42) Quadrula ebena Lea: Kelly (1899:401) Baker (1906:81) Forbes & Richardson (1913:536) Quadrula ebena (Lea) : Danglade (1914:9) Fusconaia ebena: Richardson (1928:457) Sintoxia antrosa Raf., 1820: Morrison (pers. comm., 4 January 1968) Fusconaia antrosa (Raf.) : FMNH Danglade (1914:38) considered this species as the most valuable button shell in the United States. He stated that: "Although widely distributed throughout the entire river [Illi- nois], this species is so rare in the upper stretches that often only one or two examples are found in a ton of shells. In the lower third of the river the conditions are better; the number may run as high as 2 or 3 per cent." In the early 1870's Calkins (1874:42) found the ebony shell occurring abun- dantly in the river at La Salle County (Starved Rock pool). Baker (1906:81) reported this species from the river at Utica and Havana. In the 1896-1897 period, Kelly (1899:401) examined 23 specimens of ebony shells collected in the Havana area. In 1912 Forbes & Richardson (1913:536) collected live ebony shells in the river between Chillicothe and Henry. However, in the 1924-1925 pe- riod Richardson (1928:457) was unable to find a living specimen of this spe- cies in Peoria Lake. Morrison (pers. comm., 4 January 1968) collected this species in the river at Meredosia in 1930, and in 1955 Par- malee (pers. comm., 21 November 1966) took one live ebony shell at Naples. Only one living specimen of this spe- cies was taken in the 1966 survey. This mussel was collected near the mouth of the river with the crowfoot bar on a hard bottom in 9.0 feet of water. The height of the specimen was 2.8 inches, and it was determined to be 14 years old. This species was not found in the Illinois River commercial shell piles ex- amined in 1966. Formerly, the ebony- shell was a fair- ly abundant mussel in the Illinois River as evidenced by the records presented here. Today it is rare and apparently occurs only in the lower part of the river (Alton pool). This virtual dis- appearance of the ebony shell from the Illinois River during the past 50 years probably was related to siltation and pollution rather than to any change in the fish population. The known fish host for this mussel (Baker 1928:67), the skipjack herring, Alosa chrysochloris (Rafinesque) , has always been consid- ered an uncommon species in the Illi- nois Ri\er (Forbes & Richardson 1920: 49 ; Starrett & Smith unpublished ) . Museum Records.—Chillicothe (1907 Freeland & Williams) USNM 676962; Havana area (pre- 1900 Strode) FMNH 9220 and 50574, (1894) UIMNH 22179, and (1909) INKS; Meredosia (1907 F & W) USNM 676951 and (1930 Mor- rison) USNM 678633; Naples (1955 Parmalee) ISM 1122; 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678555; 10 miles below Hardin (1907 Bartsch stat. 110) USNM 678556; and Illinois River without locality (pre- 1943 Webb Coll.) FMNH 22845. Live Mussel Records ( 1966 Survey) . — River mile 0.9-1.0 (LB). OSM 18013. Old Shell Records (1966 Survey).— River mile 15.0, 44.9, 66.0-66.4, 75.8, 86.6, 94.3, 106.8, 129.8, 145.7, 156.0, 196.3, 198.1, and 219.4. OSM 18194, 18207, 18251, 18276, 18289, 18311, 18327, 18357, 18441, and 18452. Fusconaia subrotunda (Lea, 1831) Fusconaia subrotunda (Lea) : Parmalee (1967:87) Quadrula subrotunda Lea: Baker (1906:81) Baker (1906:81) stated that F. subro- tunda was reported from the Illinois 290 Illinois Natur.'VL History Survey Bulletin Vol. 30, Art. 5 River by Call. The author was unable to locate a specimen of this species tak- en from the Illinois River. According to Simpson (1914:893) this species oc- curred in the Ohio, Cumberland, and Tennessee river systems. Parmalee (pers. comm., 29 June 1967) informed the author that: "I have never collected this in the Illinois River or in any river in the state, for that matter. Apparently this species is confined to the Ohio River and its tributaries and if it still occurs there today, it would be rare." Van der Schalie (pers. comm., 31 August 1967) considered the Illinois River out of the range for this species. Morrison (pers. comm., 27 November 1967) men- tioned that any records of this species from the Illinois River were probably misidentified (flatter) specimens of F. ebena. On the basis of the evidence the author has excluded this species from his mussel fauna list of the Illinois River (Table 5). Museum Records.—None. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. Fusconaia flava Complex A series of specimens belonging to the Fusconaia flava complex collected from the river in the 1966 survey was submitted to Dr. David Stansbery for examination. The comments and analy- sis made by Dr. Stansbery (pers. comm., 12 July 1967) concerning this complex and the Illinois River material were: "A total of 29 specimens of this form constitute our holdings of this species from the Illinois River. All but a single specimen were collected by Dr. William Starrett in 1966 and these latter specimens comprise 14 separate lots. These lots extend from Illinois River mile 1 to 111. Riv. mi. 169.3. "Each specimen was measured as to length, height, and width. A ver- nier caliper was used and each di- mension rounded off to the nearest millimeter. From these data were calculated the height index |— X 100 y width index r^x loo' /w Vh X 100 ) and transverse index was the width in- dex which Ortmann (1918, 1919, & 1920) used to differentiate the head- water forms from the downstream forms in a number of other species. "In order to work with this com- plex in Lake Erie (some years ago) I compared these same proportions of the holotypes of each of the de- scribed names in this complex. I found that (Stansbery 1960:104) there was a gradual gradation in both height and width indices from the very compressed jlava Rafin- esque, 1820, through rubiginosa Lea, 1829; parvula Grier, 1918; trigonus Lea, 1831; undatus Barnes, 1823; to wagneri Baker, 1928. The latter is the very high, very wide extreme found (then) in Lake Pepin of the Mississippi River. While I dislike to disagree with a worker of Baker's stature I must, in all honesty, con- fess that my concept of this group does not concur with his. I cannot separate any of the above described fonns into species distinct from the first described— jlava Rafinesque, 1820. "Since receiving this fine set of material from the Illinois River I have once again gone over my orig- inal measurements and calculations as well as the extensive material which has accumulated here at the Ohio State Museum in the interim. All of this has served only to con- vince me that the concept I arrived at in 1960 is the correct one. Had Baker had at his disposal the ma- terial we have for study today I Feb., 1971 Starrett: Mussels of the Illinois River 291 believe he would concur with the following arrangement. Fusconaia flava Width Index forma flava (Raf., 1820) Up to '"14* Fusconaia flava forma undata (Barnes, 1823) 55* and over *seeOrtmann 1920:282 "The names flava Raf. and un- data Barnes are used above since they are conspecific and represent the earliest names applied to the compressed and swollen forms, re- spectively. Ortmann in some in- stances used a third designation for intermediate specimens. If for any reason this becomes desirable, the form trigona Lea lies intermediate between the extremes of this com- plex. Wherever I have had the op- portunity to study all the F. flava forms within a single stream system it has proved to be a cline from F. f. flava in the headwaters to F. f. f. undata downstream. "Whether the differences observed between the headwaters and the big rivers are principally genetic or en- vironmental is not presently known and constitute a different, though not less interesting, problem. "This brings us to the question of the identification of the Illinois River Fusconaia flava specimens. The width indices of the 29 speci- mens studied varied from a low of 57 to a high of 75 thus placing all of them in the form undata. A larger sample might well produce some form flava specimens and it's almost certain that collecting in the tributaries would do so. The mean width index for all 29 specimens was 66. This means that Fusconaia flava of the Illinois River proper groups with those forms found in the Mississippi River below Minne- apolis, the lower Ohio River, lower Wabash River, and the lower White, Black, and St. Francis Rivers of Arkansas. There are a few records of this form of F. flava for the lower Cumberland and Tennessee Rivers (in Kentucky) but neither this form nor the compressed flava seem to have been able to invade the Cumberland Plateau or southern Appalachians. Related forms are present in the Gulf Coast rivers of the coastal plain from the Alabama River west to at least the Sabine River of Texas but apparently rep- resent different species." As Stansbery mentions, he was unable to separate the forms of flava discussed here into distinct species. However, van der Schalie (pers. comm., 31 August 1967) considered flava and undata to be separate species unless they were proved to be clines. Morrison (pers. comm., 27 November 1967) also treated flava and lateralis (undata) as separate species. The author has followed Stansbery's opinion relative to the F. flava complex and believes that the synonymies in- cluded below for each form will enable the reader to comprehend the form or species discussed, regardless of his opinion concerning this complex. Wabash Pig-Toe Fusconaia flava forma flava (Rafinesque, 1820) Fusconaia flava (Raf.) : Parmalee (1967:31) FMNH MCZ Unio rubiginosus Lea: Calkins (1874:44) Quadrula rubiginosa Lea: Kelly (1899:401) Quadrula rubiginosa (Lea) : Danglade (1914:9) Quadrula rubiginosa Lea {=flava Conrad) : Baker (1906:80) This headwaters and creek form of Fusconaia flava was not collected from the Illinois River in the 1966 survey. During the 1966 survey a living speci- men of the creek form flava was taken in the Aux Sable River, a tributary 292 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 stream of the upper Illinois River (OSM 17342). Calkins (1874:44) considered rubigi- nosus an abundant species in the Illinois (Starved Rock pool) and Fox rivers. Downstream from Starved Rock at Peru several specimens of F. flava were col- lected from the Illinois (pre- 19 10) and later deposited in the Museum of Com- parative Zoology. Dr. Stansbery (pers. comm., 20 January 1970) examined these museum specimens for the author and informed him that: "The F. flava I would term form flava Raf. but have the suggestion of the form trigona Lea which is one of several inter - connecting forms between flava Raf. and un- data Barnes. They do not, however, have the outline, width index, high beaks or sulcus typical of undata Barnes." Kelly (1899:401) indicated that in the 1896-1897 period he checked for parasites one specimen of this form from the river at Havana. Also Baker (1906: 80) reported that rubiginosa was taken at Havana (no mention of stream) by State Laboratory personnel. The author examined in the collections of the Field Museum of Natural History a shell col- lected at Havana (no mention of stream) in 1895 which he considered to be form flava. The Illinois River flows past the west side of Havana, but directly across from Havana, Spoon River empties into the Illinois. The author conjectured that this shell was collected either in or near the mouth of Spoon River. Danglade (1914:39) considered ru- biginosa rare in the Illinois River, and the only examples of this mussel found in his survey were taken from Peoria Lake. Stansbery mentioned above that a larger sample in 1966 of F. flava f. undata from the river might have pro- duced some specimens of the form flava and possibly Danglade's (Ibid.) records of this form (rubiginosa) were a result of examining large collections of speci- mens belonging to this complex. The tributary streams emptying into Peoria Lake were all temporary or intermittent creeks and \vere not typical streams where the form flava might be expected to occur. In the author's opinion the rec- ords cited above of form flava {rubigi- nosus and rubiginosa) occurring in the Illinois, other than Peoria Lake, were based on specimens collected at or near the mouths of tributary streams. The host fish of this form is not known. Museum Records.—Peru (pre-1910) MCZ 269572; and Havana, no stream mentioned (1895 Hay) FMNH 14898. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. Pig-Toe Fusconaia flava forma undata (Barnes, 1823) (Plate 3-14) Fusconaia undata (Barnes) : Parmalee (1967:32) Richardson (1928:457) Unio trigonus Lea: Calkins (1874:45) Quadrula trigona Lea: Kelly (1899:401) Forbes & Richardson (1913:533) Quadrula trigona (Lea) : Danglade (1914:9) Quadrula undata (Barnes) : Danglade (1914:39) Fusconaia undata undata Barnes: FMNH Fusconaia undata wagneri (Baker) : FMNH Fusconaia undata: Richardson (1928:457) Sintoxia -lateralis Raf., 1820: Morrison (pers. comm., 4 January 1968) Danglade (1914:39) considered this form the most abundant of the "pig-toe" group in the Illinois River and stated that: "Some beds, depending upon the parts worked, gave the following percentages: Chillicothe, 7; Pekin, 3; Florence, 9; and Hardin, 2." In the 1966 survey 46 live specimens of this form were taken between river Feb., 1971 Starrett: Mussels of the Illinois River 293 miles 1.0 and 170.9 (Table A-3). The pig-toe constituted 1.1 percent of the live mussels taken in the survey and ranked 11th in abundance in the 1966 collections (Tables 6 and 7). The av- erage height of these shells was 1.9 inches. Most of these shells were be- tween 8 and 12 years of age (Table A-9). No pig-toe taken in the survey or examined in the Illinois River com- mercial piles was over 2.4 inches in height (minimum commercial height 2.5 inches) . The small size and scarcity of this form in the Illinois River in 1966 virtually eliminated it as a commercial shell. Formerly the pig-toe was distributed throughout most of the river, as indicated in the museum records and by subfossil shells found in 1966. In the 1966 survey neither a living nor an old shell of this form was taken in the Starved Rock navigation pool; however. Calkins (1874:45) reported it from this pool in La Salle County. In the present study 26 live specimens were taken in the Alton pool and 19 specimens from the lower part of the Peoria pool. Only a single live pig-toe \\as collected in the La Grange pool (between Alton and Peoria pools) . In the 1896-1897 period Kelly (1899:401) took 22 pig-toes from the river at Ha- vana in the La Grange pool. In 1912 Forbes & Richardson (1913:533 & 536) collected pig-toes between Hennepin and Chillicothe. However, in the 1924-1925 period Richardson (1928:457) did not take this form above the lower end of Upper Peoria Lake. This was approxi- mately the same upstream location (river mile 170.9) where live pig-toes dropped out of the 1966 survey collections. .\ccording to Baker (1928:61) the white crappie, Pomoxis annularis Rafin- esque, and black crappie, Pomoxis nigro- maculatus (Lesueur), were believed to be the host fishes for the glochidia of the pig-toe. Both of these species, par- ticularly the black crappie, were common Table 6.—Rankings of the relative abundance of kinds of live mussels taken in the 1966 survey of the Illinois River and its bottomland lakes, based on the number of specimens collected.^ 294 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Table 7.—Rankings of the relative abundance of kinds of live mussels taken in the 1966 survey of the Illinois River and its bottomland lakes, based on the percentage of collections in which a kind of mussel occurred. ' Feb., 1971 Starrett: Mussels of the Illinois River 295 168.1-168.5 (RB), 168.6 (LB), 169.3 (RB), and 170.9 (RB). OSM 17344, 17697, 17698 (2), 17699, 17713, 17714 (6), 17728 (5), 17729 (2), 17731 (3), 17732, 17735, 17736 (2), 17737, and 17738; FMNH 156957 (3) and 156966. Old Shell Records (1966 Survey).— River mile 44.9, 66.0-66.4, 75.8, 94.3, 106.8, 129.8, 145.7, 156.0, 184.5, 196.1, 196.3-198.1, 219.4, 253.5-256.5. OSM 18193, 18277, 18288, 18310, 18326, 18356, 18381, 18429, 18440, 18451, and 18476. Washboard Megalonaias gigantea (Barnes, 1823) (Plate 1-4) Megalonaias gigantea (Barnes) : Parmalee (1967:33; 1962:9) Richardson (1928:457) MCZ Quadrula multiplicata Lea: Kelly (1899:401) Quadrula heros Say (= multiplicata Lea) : Baker (1906:78) Forbes & Richardson (1913:533) Quadrula heros (Say) : Danglade (1914:10) Amblema (Megalonaias) gigantea gigantea (Barnes) : Vmnh Megalonaias gigantea Barnes: Morrison (pers. comm., 4 January 1968) Danglade (1914:40) considered the washboard the best button shell found in the Illinois River. In 1966 this species was the second most important shell taken from the Illinois River for use in the Japanese pearl-culture industry. The washboard ranked fourth in abundance in the 1966 survey collections (Tables 6 and 7) and constituted 4.9 percent of the live shells taken (Table A-3) . Most of the washboards collected were over 2.5 inches in height (Table A-10) and 70.5 percent of them were between 11 and 18 years of age (Table A-11). In 1912 the washboard was an abun- dant shell in various parts of the river between Spring Valley (river mile 218.5) and its mouth (Danglade 1914:13-24; Richardson 1928:457). Baker (1906: 78) stated that this species had been taken from the river at Ottawa (river mile 239.5) and Utica (river mile 229.6) . These citations from the literature to- gether with the museum and subfossil shell records indicated that the wash- board formerly was distributed through- out the river upstream as far as Ottawa. No record was located relative to the occurrence of the washboard in the Mar- seilles pool. In the 1966 survey 207 live wash- boards were collected between river miles 0.9 and 196.1 (near Henry) ; however, 88.4 percent of these specimens were taken from the Alton pool between river miles 0.9 and 79.8 (Tables 8 and A-3). In the river proper no live washboard was taken between river miles 110.5 (9 miles below Havana) and 196.1. How- ever, in 1969 a few live specimens were taken by commercial fishermen just be- low Peoria Lake and in Peoria Lake. At river mile 196.1 a single live wash- board was collected by wading. Just above Havana at Quiver Lake two specimens were taken alive, one with the crowfoot bar and the other by wad- ing. In the 1896-1897 period Kelly (1899: 401) examined 26 washboards collected from the river at Havana. Danglade (1914:18) found in 1912 that wash- boards predominated the commercial shell catch at Havana. In 1912 Forbes & Richardson (1913:533 & 536) took 11 washboards at Hennepin (river mile 207.4), and they found this species to be one of the most abundant living mus- sels between Henry and Chillicothe (river mile 180.4, just above the upper end of Peoria Lake). In that same year Danglade (1914:16-17) collected wash- boards and checked commercial shell piles containing this species from Peoria Lake. Richardson (1928:456-457) did not find a live washboard in Peoria Lake during his 1924-1925 survey. He stated that only the hardier species of mussels had been able to survive the destructive pollution period of 1917-1920 in the upper river. Evidently pollution has now virtually restricted the wash- board to the lower river proper from 296 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Table 8.—Catches of washboards (Mega- lonaias gigantea) per 5 minutes of fishing with the crowfoot bar in the Illinois River proper in the 1 966 survey. Feb., 1971 Starrett: Mussels of the Illinois River 297 (RB), 72.9 (RB), 73.0 (RB), 79.8 (RB),86.6 (LB), 86.8 (LB), 93.6 (LB), 96.8 (RB), 106.0-106.9 (LB), 108.8- 109.0 (RB), 110.0 (RB), 110.1 (LB), 110.5 (RB), Quiver Lake, and 196.1 (LB). O.SM 17705-17707 and 17709; FMNH 156700 (3), 156987 (4), 156999 flO), 157005 (4), 157008 (9), and 157009(4). (1969): 162.3 (LB). OSM 22274. Old Shell Records (1966 Survey).— River mile 66.0-66.4, 75.8, 86.6-86.8, 106.8, Quiver Lake, 129.8, 145.7, 156.0, 184.5, 196.1, 219.4. OSM 18219, 18253, 18270, 18290, 18301, 18312, 18329, 18359, 18382, 18431, and 18454. Three-Ridge (Blue-Point) Amblema plicata (Say, 1817) (Plate 1-3) Amblema peruviana (Lamarck) : Parmalee (1967:27; 1962:9) MCZ Amblema costata: Parmalee (pers. comm., 21 Novem- ber 1966) MCZ Quadrula plicata Say: Kelly (1899:401) Baker (1906:78) Forbes & Richardson (1913:529) Unio undulatus Barnes: Calkins (1874:45)1 Quadrula plicata (Say) : Danglade (1914:10) Quadrula undulata Barnes: Baker (1906:78) Quadrula undulata (Barnes) : Danglade (1914:10) Amblema rariplicata: Richardson (1928:456) Parmalee (pers. comm., 21 Novem- ber 1966) 'Baker (1928:69) lists Unio undulatuB Barnes unAer Mciralonaias gigantea (Barnes). Calrs (1900: 445-446) description and Plate 13 of U. undulatus Barnes fit that of Amblema plicata (Say). Likewise, Goodrich & van der Schalie (1944:306) refer to Call's Plate 13 as Amblema costata Rafinesque. According to Stansbery (pers. comm.. 31 July 1968) : "A care- ful examination of Barnes' plate of the holotype of Unio undulatus proves it to be an eroded specimen of Mcgalonaias gigantea." The author was of the opinion that Calkins (1874:4B). like Call, was refer- ring to U. undulatus as A. plicata rather than M. gigantea. Amblema (Amblema) plicata plicata (Say) : FMNH Amblema (Amblema) plicata costata Raf.: FMNH Amblema plicata Say, 1817 (form rari- plicata Lam., 1819 included) : Morrison (pers. comm., 4 January 1968) Amblema plicata: OSM According to Parmalee (1967:26): "Some authors (for example F. C. Baker, 1928) have recognized three distinct species of Amblema: A. costata which is associated with a headwaters or small stream en- vironment; A. rariplicata, a species of medium-sized rivers, or of down- stream sections of large rivers such as the Illinois and differing from the former in the shell being some- what more elongated and inflated; and A. peruviana, the large river species showing an even greater de- gree of inflation of the shell and um- bones. On the other hand, some authorities recognize only one species, and the others are considered simply as forms or variants resulting from differences in size and depth of rivers in which they occur. Again, depend- ing upon the author consulted, the names Crenodonta peruviana or Amblema plicata are used." A series of specimens of the genus Amblema collected in 1966 from the Illinois River was identified by Dr. David Stansbery as Amblema plicata f. plicata (Say, 1817). Concerning this complex Stansbery (pers. comm., 1 December 1967) stated: "The only type material of Unio plicata Say, 1817, that I could locate was at the Philadelphia Academy. ... It is obviously a Lake Erie specimen as labeled, fits the descrip- tion by Say, and has all the char- acteristics of Unio peruviana La- marck, 1819, except size. This latter is to be expected since all the true 298 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 stream species found in Lake Erie are, without exception, stunted. "Since Unio plicata Say, 1817, was the first plicate naiad described from North America the name has priority. Since the smaller individu- als of this complex from the Missis- sippi Riser, Ohio River, and Illinois River cannot be distinguished from these Lake Erie specimens (except for size) I conclude that U. peru- viana Lamarck, 1819, and U. rariplicata Lamarck, 1819, are the same species and hence synonyms of U. plicata Say, 1817. "All of the forms of this complex in the Ohio River drainage & Great Lakes drainage are abundantly con- nected by intermediates. None is clear cut — they all 'run together.' Therefore there can be but one species. The earliest name is U. plicata Say, 1817, as I indicated in 1961 (1961:3, 4, & 7). "In spite of the fact that all forms in the drainage concerned are con- nected by intermediates there are extremes. These extremes are the compressed form costata Raf., 1820, found in the headwaters and the in- flated form plicata Say, 1817, found in the big rivers (and in river-lakes such as Lake Erie) . Lake Erie is in so many ways a big river with a few peculiarities of its own. Our Lake Erie A. plicata specimens include many form plicata, some form costa- ta, and intermediates of every de- scription but all somewhat stunted. No extremes of form costata have been taken, to my knowledge, from Lake Erie. "The compressed costata form of A. plicata is not geographically de- finable .... It is related only to habitat—to the headwaters. We do not know whether it is genetically different from the swollen plicata form or not. Hence, it is not de- finable as a subspecies. It is rec- ognizable as a form .... "If we recognize forms, since costata Raf., 1820, is the first name given to the headwater form, Amhle- rna plicata form costata Raf., 1820, should be used. Since the type is the swollen form, Amblema plicata form plicata (Say, 1817), should be used for it." The author checked two specimens taken before 1918 at Havana in the col- lections of the Field Museum of Natural History (FMNH 68177) , and these speci- mens were compressed much as is the form costata. Otherwise, all of the speci- mens from the river examined by the author were the swollen form plicata. In 1966 the three-ridge was the most abundant mussel in the Illinois River and made up 62.4 percent of the live mussels taken in the 1966 survey (Tables 6, 7, and A-3) . It was also the most important mussel taken commercially and formed 74.8 percent of the shells examined in the sorted commercial shell piles along the river (Alton pool). In the 1966 survey live mussels of all species were col- lected only in the three lower navigation pools, and in these pools the three-ridge accounted for the following percentages of live mussels taken: 56.9 percent in the Alton pool, 61.4 percent in the La Grange pool, and 81.2 percent in the Peoria pool. Of the 2,650 live three-ridges collected in 1966, 85.7 percent were 2.0-3.0 inches in height (Table A-12) and 87.5 percent were 7-15 years of age (Table A-13). The largest estimated standing crop of live mussels in the 1966 survey was 3,508 pounds (shell weight) per acre of three-ridges at river mile 162.3 (LB) just below the lower end of Peoria Lake. The three-ridge was one of the more pollution-tolerant species of mussels found in the study, which probably accounts for its wide distribution and abundance in the river. In the upper sections of the La Grange pool (river miles 140.5- 156.6) and Peoria pool (river miles 174.9 -229.3) the three-ridge was found in small numbers but was one of the few species able to survive in those areas of the river (Table A-3) . Severe pollution conditions existed in the river upstream from Peoria between 1917 and 1920, and Richardson (1928:456) mentioned that the three-ridge was the only one of the Feb., 1971 Starrett: Mussels of the Illinois River 299 16 species of mussels found in Peoria Lake in the 1924-1925 period that occurred in more than very' scanty numbers. The aspects of pollution affecting the three- ridge and other mussels are discussed further in the next section of this paper. In the 1966 survey subfossil three-ridge shells were taken upstream as far as river miles 253.5-256.5 in the Marseilles pool. Calkins (1874:45) collected undulatus from the river in La Salle County, Baker (1906:78) reported that undulata was taken by Handwerk at Starved Rock, and an Ohio State Museum specimen was col- lected there in the 1800's. In 1912 Forbes & Richardson (1913:528) took live three- ridges as far upstream as Starved Rock. Danglade (1914: 13-25) found the three- ridge (blue-point and three-ridge com- bined) to be the most abundant mussel at the majority of his stations on the river between Henry and Grafton in 1912. Baker (1928:74-75) reported that crappies were host fishes for the glochidia of the three-ridge. Recently in the labora- tory Stein (1968:46) successfully re- covered metamorphosed juveniles of A. plicata from infections of the yellow perch, Perca jlavescens (Mitchill) ; rock bass, Ambloplites rupestris (Rafinesque) ; green sunfish, Lepomis cyanellus Rafin- esque; bluegill, Lepomis macrochirus Ra- finesque; and pumpkinseed, Lepomis gib- bosus (Linnaeus). She was unable to infect several species of minnows, cat- fishes, and gars with glochidia of this mussel. The bluegill, green sunfish, and both species of crappies were all common fishes in the Illinois River during the 1960's. Museum Records. — Starved Rock (pre- 1900) OSM 10068; Peru (pre- 1910) MCZ; Peoria (1931 Morrison) USNM 678634; between Peoria and Pekin (1908 Freeland & Williams) USNM 678.594; Pekin (1907 F & W) FMNH 11206; 3 miles SE of Banner (1953 Parmalee) ISM 111 (dead); be- tween Pekin and Havana (1908 F & W) USNM 678595; Liverpool (1957 Parma- lee) ISM 2260; 2 miles N of Havana (1955 Parmalee) ISM 1008-1015; Ha- vana (1909 Freeland) USNM 677769, (1894 Baker) UIMNH 22149, (1909) INHS, and (pre-1918 Hand Coll.) FMNH 68177; Frederick (pre-1943 Webb Coll.) FMNH 20216; 2 miles N of Beardstown (1959 Parmalee) ISM 2868; Beardsto\vn (pre-1943 Webb Coll.) FMNH 22533 and (pre-1910) MCZ; Meredosia (1907 F & W) USNM 677036. (1930 Morrison) USNM 678635-678636, (1932 Morri- son) USNM 678637, (pre-1910) MCZ, and (1955 Parmalee) ISM 1407-1412; Naples (1912 Danglade) USNM 678596 and (1955 Parmalee) ISM 1112-1117; Valley City (1909 Freeland) USNM 677766; Florence (Freeland) USNM 678592; Montezuma (shell pile) USNM 678593; Pearl (1909 F & W) USNM 677770 and (1965 Par- malee) ISM 3312; 1 mile N of Hardin (1956 Parmalee) ISM 2203 (dead); Hardin (1907 F & W) USNM 676943; 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678557; 10 miles below Hardin (1907 Bartsch stat. 110) USNM 678558; 2 miles above Grafton (1907 Bartsch stat. HI) USNM 678559; and Illinois River without locality (pre-1900) OSM 23993 (dead). Live Mussel Records ( 1966 Survey) . — River mile 0.9-1.0 (LB), 5.4-5.5 (RB), 10.3-10.5 (RB), 11.8-12.1 (LB), 13.0 (RB), 13.2-13.5 (LB), 14.9-15.1 (RB), 19.2-19.4 (RB), 20.6-20.8 (LB), 21.7- 22.0 (RB), 24.2-24.4 (LB), 25.8-26.0 (LB), 27.9 (LB), 28.9-29.1 (RB), 30.5- 30.8 (RB), 33.2-33.5 (RB), 35.9-36.1 (LB), 36.1-36.3 (RB), 37.3-37.6 (RB), 39.1-39.3 (RB), 40.3-40.5 (RB), 40.5- 40.7 (LB), 42.2-42.3 (LB), 42.3 (RB), 45.3-45.9 (LB), 47.4-47.7 (LB), 48.3 (RB), 51.0-51.3 (RB), 51.2 (LB), 53.6 (LB), 53.8 (LB), 54.3 (RB),54.4 (RB), 56.3 (LB), 56.6 (LB), 57.5-57.7 (LB), 57.6 (RB), 58.0 (RB), 58.9 (RB), 60.8 (RB),60.8 (LB), 62.4 (RB),62.6 (RB), 62.6 (LB), 63.8 (LB), 64.4 (LB), 64.4 (RB), 66.0-66.6 (LB), 66.9 (RB), 68.3 (RB),68.3 (LB), 68.6 (RB) , 68.9 (RB), 68.9 (LB), 69.0 (RB), 69.4 (RB), 72.0 (LB), 72.9 (RB), 73.0 (RB),73.7 (RB), 73.7 (LB), 74.6 (RB), 75.8 (RB), 79.8 (RB), 79.8 (LB), 86.4 (LB), 86.6 (LB), 86.8 (LB), 87.3 (RB), 87.9 (LB), 93.4- 93.6 (LB), 95.6 (RB), 95.8 (LB), 96.8 (RB),98.0 (LB), 99.0-99.5 (RB), 100.0- 300 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 100.5 (LB), 106.0-106.9 (LB), 108.2- 108.3 (RB), 108.8-109.0 (RB), 110.0 (RB), 110.0-110.2 (LB), 110.5 (LB), 112.1-112.5 (RB), 113.2-114.0 (LB), 115.3 (RB), 121.9-122.0 (LB), 122.2 Quiver Lake (LB), 122.8 Quiver Lake (LB), 129.8-130.4 (RB), 132.1 (RB), 135.0 (RB), 145.7 (RB), 148.5 (LB), 154.3-154.5 (RB), 155.9-156.4 (RB), 156.4-156.6 (LB), 159.4 (LB), 161.1- 161.3 (LB), 161.2 (RB), 161.7-161.8 (LB), 162.3 (LB), 163.0 (LB), 164.4- 165.1 (LB), 164.5-164.9 (RB), 165.2 (RB), 165.3 (LB), 166.3 (LB), 166.6 (LB), 167.2 (RB), 167.2 (LB), 167.5- 167.7 (LB), 168.1-168.3 (LB), 168.1- 168.5 (RB), 168.6 (LB), 169.3 (RB), 169.5 (LB), 170.8-171.8 (RB), 173.0 (RB), 174.1-174.9 (RB), 174.1 (LB), 184.5 (RB), 184.6 (RB), 184.8 (RB), 191.5 (LB), 196.1 (LB), 205.0 (RB), and 228.3 (RB) . OSM 17711, 17720, 17742, 17747, 17749, 18126 (6), 18127 (5), 18128 (4), 18130 (4), 18131 (4), 18132 (3), 18133 (3), 18135 (3), 18136 (4), 18138 (4), 18139 (4), 18140 (4), 18141 (4), 18142 (4), 18143 (3), 18144 (3), 18145 (4), 18146 (2), 18147 (4), 18148 (2), 18149 (2), 18150 (2), 18151 (3), 18152 (3), 18153, 18154 (4), 18155 (4), 18156 (5), 18157 (5), and 18158; FMNH 156952 (5), 156954 (4), 156955 (3), 156958 (14), 156959 (26), 156972 (10), 156975 (3), and 156977 (7). Old Shell Records (1966 Survey).— River mile 66.0-66.4, 75.8, 86.6-86.8, 94.3, 106.8, 145.7, 156.0, 184.5, 196.1, 196.3-198.1, 219.4, and 253.5-256.5. OSM 18218, 18252, 18269, 18278, 18291, 18328, 18358, 18430, 18442, 18453, and 18477. Maple-Leaf Quadrula quadrula (Rafinesque, 1820) (Plate 1-6) Quadrula quadrula Raf. : Parmalee (1967:43; 1962:9) Richardson (1928:457) Morrison (pars, comm., 4 January 1968) MCZ Quadrula asperrima Lea: Kelly (1899:401) Forbes & Richardson (1913:533) Quadrula lachrymosa Lea (= quadrula Say, asperrimus Lea) : Baker (1906:79) Quadrula lachrymosa (Lea) : Danglade (1914:10) Quadrula fragosa Conrad: Baker (1906:79) Quadrula fragosa (Con.) : Danglade (1914:9) Quadrula (Quadrula) quadrula quadrula (Raf.) : FMNH Baker (1906:79) and Danglade (1914:9 & 10) included both Quadrula fragosa and Quadrula lachrymosa as oc- curring in the Illinois River. Relative to the occurrence of fragosa in the Illinois River Danglade (1914:40) stated: "Rare; an example was found in Peoria Lake, but it does not agree exactly with fragosa as we found it in the Cumberland River, near Clarksville, Tenn." At a later date Baker (1928:89) wrote: "Fragosa appears rare in Wisconsin and Illinois .... The nearest ap- proach in Illinois is found among specimens from Spoon River." A large series of maple-leafs collected in the 1966 survey was studied by Dr. Stansbery, and he identified them as Quadrula quadrula. However, he did mention (pers. comm., 26 September 1967) that the specimens had suggestions of the fragosa (Conrad) description but that they were not distinguishable from his museum specimens of Q. quadrula from the Ohio River proper (type locale) . Specimens from the Illinois River ex- amined by the author were likewise Q. quadrula, 'including several museum specimens labeled fragosa. In this paper the author has treated the Illinois River fragosa records in the literature as being Q. quadrula. In the 1966 survey the maple-leaf comprised 9.2 percent of the live mussels taken and ranked third in abundance (Tables 6 and 7). Because of its small size, this species was of little importance in satisfying the commercial demand in 1966. Of the 390 live specimens collected in the survey, 86.9 percent were 7-13 years of age (Table A- 14) and 85.1 per- Feb., 1971 Starrett: Mussels of the Illinois River 301 cent ranged from 1.7 to 2.5 inches in height (Table A-15). The maple-leaf was more abundant in collections made in the Alton pool than those made in the La Grange and Peoria pools (Table A-3). In the Alton pool at river mile 72.9 (RB) a standing crop of 303 pounds per acre (shell weight) of live maple-leafs was estimated. Live specimens of this species were taken between river miles 0.9 and 210.7 (Table A-3) . In the upper part of the La Grange pool (river miles 140.5-156.6), consid- ered by the author as poor mussel habitat because of pollution, a series of eight live maple-leafs was taken. However, in the Peoria pool no live maple-leaf was collected between river mile 167.7 (lower end of Middle Peoria Lake) and mile 210.7 (between Hennepin and Spring Valley). At mile 210.7 a single live maple-leaf was taken. In the entire up- per part of the Peoria pool (river miles 174.9-229.3) only 38 live mussels of all species were collected in 1966. The paucity of mussels in this part of the river was thought by the author to have been caused by pollution. As mentioned earlier, no live mussel was taken above mile 229.3. The presence of maple-leafs in the upper part of the La Grange pool indicated that this species was somewhat tolerant of pollution, but the virtual ab- sence of the species above river mile 167.7 tended to contradict this opinion. Pos- sibly the host fish of the maple-leaf was either scarce or absent in the upper section of the Peoria pool; however, the author was unable to ascertain the host species of this mussel (Coker 1921:23; Baker 1928:86). At the Field Museum of Natural His- tory the author examined a maple-leaf taken from the river at Ottawa (Starved Rock pool). Richardson (1928:456-457) stated that in 1912 the maple-leaf oc- curred upstream as far as Spring Valley (river mile 218.5). In 1912 Danglade (1914:40) did not consider the maple- leaf common but mentioned that it oc- curred in small numbers in most of the mussel beds in the river. Since Danglade's study of the river many species of mussels have disappeared or decreased in abun- dance. As a result of these changes, in 1966 the maple-leaf was relatively one of the most abundant species present, particularly in the Alton pool. The maple- leaf was limited in its distribution in 1966 (with the exception of the single record upstream at river mile 210.7) from Mid- dle Peoria Lake to Grafton, whereas formerly it ranged from Ottawa to Graf- ton. Museum Records.—Ottawa FMNH 22686; La Salle (pre-1910) MCZ; Peru (pre- 19 10) MCZ; Lake Senachwine (1934) INHS; Peoria Narrows (1924) INHS H-4; Peoria (1912 Danglade) USNM 678597; Quiver Lake (1955 Parmalee) ISM 1016-1021; Havana (1894 Baker) UIMNH 22177, (1895 Hay) FMNH 14131, and (1912) INHS a- 102; 2 miles N of Beardstown (1959 Parmalee) ISM 2866-2867; Beardstown (pre-1910) MCZ; Meredosia (1930 Mor- rison) USNM 678638-678639, (1932 Morrison) USNM 678640, (pre-1910) MCZ, and (1955 Parmalee) ISM 1394- 1400; Naples (1955 Parmalee) ISM 1140-1144; and Pearl (1965 Parmalee) ISM 3305-3307. Live Mussel Records (1966 Sur- vey) .—River mile 0,9-1.0 (LB), 5.4-5.5 (RB), 10.3-10.5 (RB), 13.2-13.5 (LB), 14.9-15.1 (RB), 19.2-19.4 (RB) , 24.2- 24.4 (LB), 25.8-26.0 (LB), 27.9 (LB), 29.0 (RB), 30.5-30.8 (RB), 33.2-33.5 (RB), 37.3-37.6 (RB), 39.1-39.3 (RB), 39.2 (LB), 40.3-40.5 (RB), 42.2-42.3 (LB), 45.3 (LB), 45.4-45.9 (LB), 48.3 (RB), 51.0-51.3 (RB), 51.2 (LB), 53.8 (LB), 54.3-54.4 (RB), 56.3 (LB), 57.5- 57.7 (LB), 57.6 (RB), 58.0 (RB), 58.9 (RB) , 62.4 (RB) , 62.6 (RB) , 63.8 (LB) , 64.4 (LB), 64.4 (RB), 66.0-66.4 (LB), 66.5 (LB), 66.6 (LB), 66.9 (RB), 68.3 (RB) , 68.6 (RB) , 68.9 (RB) , 69.0 (RB) , 72.9 (RB), 73.0 (RB), 73.7 (RB), 73.7 (LB), 74.6 (RB), 75.8 (RB), 79.8 (RB), 86.4 (LB), 86.6 (LB), 86.8 (LB), 87.9 (LB), 91.5 (RB), 93.4-93.6 (LB), 95.8 (LB), 98.0 (LB), 99.0-99.5 (RB), 100.0- 100.5 (LB), 106.0-106.9 (LB), 110.0 (RB), 110.0-110.2 (LB), 110.5 (LB), 110.5 (RB), 113.2-114.0 (LB), 115.3 (RB), 118.4 (RB), 121.9-122.0 (LB), 122.2 Quiver Lake (LB), 122.8 Quiver 302 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Lake (LB), 125.5 (RB), 129.8-130.4 (RB), 132.1 (RB), 135.0 (RB), 154.3- 154.5 (RB), 155.7-156.0 (LB), 161.1- 161.3 (LB), 161.7-161.8 (LB), 162.3 (LB), 166.3 (LB), 167.2 (RB), 167.2 (LB), 167.5-167.7 (LB), and 210.7 (RB). OSM 17354, 17355 (7), 17356 (11), 17357, 17358 (3), 17359, 17360, 17361 (7), 17362 (2), 17363 (4), 17364- 17368, 17369, (6), 17370 (4), 17371 (3), 17372 (7), 17373 (6), 17374 (3), 17375, 17376 (3), 17377 (4), 17378 (5), 17379, 17380 (2), 17381 (4), 17382 (2), 17383 (2), 17384 (2), 17385 (11), 17386 (2), 17387 (2), 17388 (3), 17389 (16), 17390, 17391, 17392 (7), 17393 (3), 17394 (9), 17395 (5), 17396 (3), 17397 (4), 17398 (26), 17399 (21), 17400 (3), 17401 (5), 17402 (6), 17403, 17404 (8), 17405 (3), 17406 (5), 17407, 17408 (4), 17409, 17410, 17411 (4), 17412 (6), 17413 (2), 17414 (5), 17415 (19), and 17416 (7) ; FMNH 156950 (7), 156953 (14), 156956 (5), 156965 (5), and 156970 (10). Old Shell Records (1966 Survey).— River mile 44.9, 66.0-66.4, 75.8, 83.0, 94.3, 106.8, Quiver Lake, 129.8, 156.0, 196.3-198.1. OSM 18195, 18264, 18280, 18292, 18302, and 18443. Pimple-Back (Warty-Back) Quadrula pustulosa (Lea, 1831) (Plate 1-5) Quadrula pustulosa (Lea) : Parmalee (1967:40; 1962:9) Forbes & Richardson (1913:531) Danglade (1914:9) Coker (1921:23) Richardson (1928:457) OSM Unio pustulosus Lea: Calkins (1874:44) Quadrula pustulosa Lea: Kelly (1899:401) MCZ Quadrula pustulosa Lea (= dorfeuilliana Lea, schoolcraftensis Lea) : Baker (1906:79-80) Quadrula (Pustulosa) pustulosa pustulosa (Lea) : FMNH Quadrula bullata Raf., 1820: Morrison (pers. comm., 4 January 1968) The pimple-back was the second most abundant mussel taken in the 1966 survey (Tables 6 and 7) and it constituted 10.0 percent of all live mussels collected (Table A-3). Even though this species ranked second in abundance, its distribu- tion was limited in 1966. In the river proper live pimple-backs were taken only between river miles 0.9 and 113.7 (about 6 miles below Havana, Table A-3) . Three live specimens were collected in Quiver Lake, just above Havana. In 1969 the author obtained from a commercial mus- sel fisherman a live specimen of this species taken just below Peoria Lake at river mile 162.3. Most of the pimple- backs were taken in the Alton pool where they made up 14.7 percent of the catch and ranked second in abundance. The highest estimated standing crop of live pimple-backs in the Alton pool was 127 pounds per acre (shell weight) at river mile 42.3 (LB). In the La Grange pool the pimple-back ranked seventh in abundance and constituted 2.2 percent of the catch. Coker (1921:23) mentioned that the pimple-back seldom attained a length of more than 2.5 inches. This was true for this species in the Illinois River in 1966, since only 3.5 percent of the 426 live pimple-backs taken were over 2.5 inches in length. All of these specimens were less than 2.5 inches in height (Table A- 16) and 90.8 percent of them were between 6 and 12 years of age (Table A-17) . The Japanese market demanded pimple-backs of 2.5 inches or more in height. The pimple-backs noted in the sorted commercial piles along the river were nearly all below the desired com- mercial size. Therefore, this species from the Illinois River was of little or no value for the Japanese market. Concerning the button industry, where size was of less importance than in the pearl-culture industry, Coker (1921:23) considered the pimple-back one of the best mussels occurring in the Illinois River. Danglade (1914:40) found in 1912 that: "The pustulosa, or warty-back, is a very common shell in the Illinois, certain very productive beds yielding a large per cent of the output." He was referring to the use of the pimple- back in the button industry. In the 1966 survey subfossil shells of the pimple-back were taken at various locations along the river including the Feb., 1971 Starrett: Mussels of the Illinois River 303 Marseilles pool. Calkins (1874:44) col- lected this species from the river in La Salle County (Starved Rock pool). In 1912 Forbes & Richardson (1913:531) found that owing to pollution at Spring Valley (river mile 218.5) all of the mus- sels they collected were dead except one pimple-back. Danglade (1914:37) listed the pimple-back as occurring in the river in 1912 at all of his stations between Henry and Grafton. In the 1924-1925 period Richardson (1928:457) collected the pimple-back in Lower Peoria Lake. Formerly the pimple-back was dis- tributed throughout much of the river proper, but in 1966 it was limited chief- ly to the lower part of the river. The present limited distribution of the pim- ple-back was probably the result of pol- lution. According to Baker (1928:92) the channel catfish, Ictalurus punctatus (Rafinesque) , was the known host fish for the pimple-back. The author has collected channel catfish in all five navi- gation pools. However, it occurred much more abundantly in the Alton and La Grange pools than in the upper three pools. Apparently the potentiality has existed for distributing young pimple- backs by the channel catfish throughout the entire La Grange pool and the low- er part of the Peoria pool, but the spe- cies has been unable to reestablish itsejf because of unsuitable environmental con- ditions in this part of the river, except in the lower part of the La Grange pool and in the vicinity of Peoria. Museum Records. — Peru (pre- 1910) MCZ; Utica (Baker) FMNH 68035; Pe- oria (1870's) BK; between Pekin and Havana USNM 677043; Quiver Lake (1955 Parmalee) ISM 1002-1007; Ha- vana (1894 Baker) UIMNH 22182, (1895 Hay) FMNH 14129, (1912) INHS a-107, (pre-1917 Zetek) FMNH 67964; Meredosia (1930 Morrison) USNM 678641-678642, (1932 Mor- rison) USNM 678643, and (1955 Par- malee) ISM 1404-1405; Naples (1955 Parmalee) ISM 1130-1135; Pearl (1965 Parmalee) ISM 3308-3309; 1 mile be- low Hardin (1907 Bartsch stat. 108) USNM 678560; 10 miles below Hardin (1907 Bartsch Stat. 110) USNM 678561; and Illinois River without locality (pre- 1900) OSM 10092. Live Mussel Records ( 1966 Survey). — River mile 0.9-1.0 (LB), 10.5 (RB), 11.8-12.1 (LB), 13.0 (RB), 13.2-13.5 (LB), 14.9-15.1 (RB), 19.2-19.4 (RB), 20.6-20.8 (LB), 24.2-24.4 (LB), 29.0 (RB), 30.5-30.8 (RB), 33.2-33.5 (RB), 37.3-37.6 (RB), 39.1-39.3 (RB), 39.2 (LB), 40.3-40.5 (RB), 42.2-42.3 (LB), 45.3 (RB), 45.3 (LB), 45.4-45.9 (LB), 47.4-47.7 (LB), 48.3 (RB), 51.0-51.3 (RB), 51.2 (LB), 53.6 (LB), 53.8 (LB), 54.3 (RB), 54.4 (RB), 56.3 (LB), 57.5- 57.7 (LB), 58.0 (RB), 58.9 (RB), 60.8 (RB), 62.4 (RB), 62.6 (RB), 62.6 (LB), 63.8 (LB), 64.4 (LB), 66.0-66.6 (LB), 66.9 (RB),68.3 (RB),68.6 (RB), 68.9 (LB), 69.0 (RB), 72.9 (RB), 73.0 (RB), 74.6 (RB), 75.8 (RB), 79.8 (RB), 79.8 (LB), 98.0 (LB), 106.0- 106.9 (LB), 110.0 (RB), 113.7 (LB), and Quiver Lake. OSM 17345, 18129 (2), 18134, 18137 (3); FMNH 156970 (2), 156982 (7), 156983 (5), 157002 (13), and 157004 (5). (1969): 162.3 (LB). OSM 22276. Old Shell Records (1966 Survey).— River mile 44.9, Meredosia Lake, 66.0- 66.4, 75.8, 94.3, 106.8, Quiver Lake, 129.8, 145.7, 156.0, 196.1, 196.3-198.1, 219.4, and 253.5-256.5. OSM 18196, 18254, 18262, 18281, 18293, 18303, 18313, 18330, 18360, 18432, 18444, 18455, and 18478. M'arty-Back Quadrula nodulata (Rafinesque, 1820) (Plate 2-7) Quadrula nodulata (Raf.) : Parmalee (1967:39; 1962:9) Quadrula nodulata Raf., 1820: Morrison (pers. comm., 4 January 1968) Unio pustulatus Lea: Calkins (1874:44) Quadrula pustulata Lea: Kelly (1899:401) Baker (1906:80) Quadrula pustulata (Lea) : Danglade (1914:9) Quadrula (Pustulosa) nodulata (Raf.) : FMNH The warty-back ranked seventh in abundance (Tables 6 and 7) and ac- counted for 1.6 percent of the live mus- sels taken in the 1966 survey (Table A- 3 ) . Sixty-eight live warty-backs were collected between river miles 0.9 and 304 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 95.8 (below Browning). However, 92.6 percent of these specimens were taken in the Alton pool, and in that pool the species ranked fifth in abundance. The warty-backs collected in the survey ranged from 5 to 14 years in age (Table A- 18). No specimen of this species tak- en in the 1966 Illinois River collections exceeded 2.0 inches in height, and the warty-back was therefore too small to have any value for the pearl-culture in- dustry. According to Danglade (1914: 39), in 1912 the warty-back was usually classed with the pimple-back {Q. pus- tulosa) but was of lesser quality for use in the button industry. Calkins (1874:44) reported collecting this species from the river in La Salle County (Starved Rock pool). Forbes & Richardson (1913) did not collect the warty-back in their 1912 survey between Morris and Chillicothe. However, in 1966 a subfossil shell of this species was taken from that section of the river at river mile 196.1 (Henry). Danglade (1914:39) stated that the warty-back was distributed generally throughout the river but occurred in very small numbers. However, in his 1912 survey (Danglade 1914:37) he did not record taking this species any farther upstream than Havana. In the period of 1896- 1897, Kelly (1899:401) examined 20 warty-backs collected at Havana. The museum records of this species listed be- low were limited to specimens from the lower river. Likewise, the subfossil shells of the warty-back taken in 1966 were all confined to the lower river except for the one record at river mile 196.1. Apparently this species was not common in the Illinois River above Havana even before 1913, and it seems to have been eliminated from the middle and upper river by pollution before 1920. Possible fish hosts for the warty-back listed by Baker (1928:96) were the white crappie ; black crappie ; large- mouth bass, Micropterus salmoides (La- cepede) ; and bluegill. All of these fish species occurred in the river. Museum Records.—Havana (pre- 1900 Strode) FMNH 50478, (1894 Baker) UIMNH 22178, and (1895 Hay) FMNH 14130; Meredosia (1930 Mor- rison) USNM 678644-678645, (1932 Morrison) USNM 678646, and (1955 Parmalee) ISM 1401-1403; Naples (1955 Parmalee) ISM 1136-1139; Pearl (1965 Parmalee) ISM 3304; and 1 mile below Hardin (1907 Bartsch Stat. 108) USNM 678562. Live Mussel Records ( 1966 Survey). — River mile 0.9-1.0 (LB), 11.8-12.1 (LB), 13.0 (RB), 21.7-22.0 (RB), 33.2-33.5 (RB), 37.3-37.6 (RB), 39.1- 39.3 (RB), 40.5^0.7 (LB), 42.3 (LB), 45.3 (RB), 45.3 (LB), 45.4-45.9 (LB), 47.4-47.7 (LB), 54.3 (RB), 62.4 (RB), 64.4 (LB), 66.0-66.4 (LB), 66.5 (LB), 66.9 (RB), 73.0 (RB), 73.7 (LB), 74.6 (RB), 75.8 (RB), 86.6-86.8 (RB), 86.8 (LB), 95.8 (LB). OSM 17338, 17339 (2), 17340 (3), 17341, 17346 (14), 17348 (9), 17349, 17350, 17351 (3), 17352, and 17353; FMNH 156947 (4), 156948, and 156992 (2). Old Shell Records (1966 Survey).— River mile 44.9, 75.8, 83.0, 86.6-86.8, and 196.1. OSM 18197, 18265, 18271, and 18433. Monkey-Face Quadrula metanevra (Rafinesque, 1820) Quadrula metanevra (Raf.) : Parmalee (1967:39; 1962:9) Danglade (1914:10) Unio metanevrus Raf.: Calkins (1874:43) Quadrula metanevra Raf.: Kelly (1899:401) Baker (1906:79) MCZ Quadrula metanevra wardii Lea: Baker (1906:79) Quadrula (Orthonymus) metanevra (Raf.) : FMNH Danglade (1914:40) considered the monkey-face a rare species in the Illinois River. In his 1912 survey (1914:37) he took a few specimens at Peoria Lake, Bath, the old La Grange locks, Mere- dosia, Bedford, Pearl, and Grafton (pos- sibly the Mississippi River) . In 1874 Calkins (1874:43) reported that the monkey-face occurred abundantly in the upper river (Starved Rock pool). In the early 1930's Morrison (pers. comm., 27 November 1967) did not collect a live specimen of this species at Mere- dosia. Likewise, Parmalee (pers. comm., 21 November 1966) did not take a live monkey-face in his collections in the Feb., 1971 Starrett: Mussels of the Illinois River 305 lower river in the 1950's. However, he did collect subfossil shells of this species at Naples and Meredosia. No live speci- men of this species was taken in our 1966 survey, but a few subfossil shells were found between river miles 94.3 and 219.4. Baker (1928:99) stated that: "Aletanevra is a species of both large and small rivers where it lives in the channel on a gravel bottom in deep water, where there is a good cur- rent .... Rare on a mud bottom." The scarcity of the monkey-face in the middle and lower parts of the river, even before 1913, probably was related to the scarcit)' of gravel bottoms in that section of the river. The upper river, before dams were constructed and pol- lution became severe, may have pro- vided a more suitable environment for this species than the middle and lower river. The bluegill and the sauger, Stizo- stedion canaderue (Smith), were re- ported by Baker (1928:99) as the host fishes for the monkey-face. The blue- gill was a common fish in the lo\ver three pools of the river, but the sauger was uncommon. Museum Records.— Starved Rock (pre- 1904 Conrad) FMNH 68124; La Salle (pre-1910) MCZ; and Havana INHS. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Sur\'ey).-- River mile 94.3, 145.7, 156.0, and 219.4. OSM 18279, 18331, 18361, and 18456. Buckhom (Pistol-Grip) Tritogonia verrucosa (Rafinesque, 1820) Tritogonia verrucosa (Barnes) : Parmalee (1967:43; 1962:9) Unio tuberculatus Barnes: Calkins (1874:45) Tritogonia tuberculata Barnes: Baker (1906:70) Forbes & Richardson (1913:531) Richardson (1928:458) MCZ Tritogonia tuberculata (Barnes) : Danglade (1914:10) Tritogonia verrucosa Raf., 1820: Morrison (pers. comm., 4 January 1968) MCZ Tritogonia verrucosa verrucosa (Raf.) : FMNH In 1912 Danglade (1914:43) con- sidered the buckhom widely distributed but comparatively rare in the Illinois River. Calkins (1874:45) found -in the early 1870's that this species occurred abundantly in the upper river (Starved Rock pool). Danglade (1914:37) re- ported taking the buckhorn at most of his stations on the river between Henry and Grafton. In 1912 Forbes & Rich- ardson (1913:531-537) did not take the buckhorn in their collections at Henne- pin but did collect it in the Illinois River opposite Lake Depue and in the river between Henry and Chillicothe. This species was not taken in Peoria Lake in the 1924-1925 period by Richardson (1928:457^58). In 1930 Morrison (pers. comm., 4 January 1968) collected live buckhorns from the river at Mere- dosia. Twenty-five years later Parmalee (pers. comm., 21 November 1966) also took live specimens of this species at Meredosia ; however, he did not take a live buckhorn at any of his other collect- ing stations in the river in the 1950's. No live specimen of this species was col- lected from the river in the 1966 survey; however, two buckhorns were taken alive in 1969 by a commercial mussel fisher- man from the river at Peoria just below Peoria Lake. This species possibly still occurs in the Alton pool, as indicated by Parmalee's 1955 record at Meredosia. Apparently the buckhorn had disap- peared from the river above Peoria be- fore 1924 (Richardson 1928:457-458) as a result of pollution and is now rare in the lower part of the Peoria pool and possibly in the Alton pool. The mu- seum and old shell records and litera- ture citations presented here indicated that the buckhorn formerly occurred in all of the navigation pools of the river. The host fish of the buckhorn is not known. Museum Records.—Peru (pre-1910) MCZ; Peoria (1870's) BK and (1878) INHS; between Pekin and Havana (1907 Freeland & Williams) USNM 678598: Havana (1894 Baker) UIMNH 22176, (1895 Hay) FMNH 8342, and (1910 Zetek) FMNH 59188 and 68172; Grand Point (possibly Grand Island near Bath) (Freeland) USNM 678599; 306 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Meredosia (pre-1910) MCZ, (1930 Morrison) USNM 678647-678648, and (1955 Parmalee) ISM 1419-1420; and Naples (1955 Parmalee) ISM 1094-1095 (dead). Live Mussel Records ( 1966 Survey). — None. (1969): River mile 162.3 (LB). OSM 22275. Old Shell Records (1966 Survey).— River mile 44.9, 106.8, 145.7, 156.0, 219.4, and 253.5-256.5. OSM 18198, 18294, 18332, 18362, 18457, and 18480. Purple Warty-Back Cyclonaias tuberculata (Rafinesque, 1820) Cyclonaias tuberculata Raf . : Parmalee (1967:27; 1962:9) Unio verrucosus Barnes: Calkins (1874:46) Quadrula tuberculata Bar. : Kelly (1899:401) Quadrula granifera Lea: Kelly (1899:401) Baker (1906:82) Quadrula tuberculata Raf. (= verrucosa Barnes) : Baker (1906:81-82) Quadrula granifera (Lea) : Danglade (1914:9) Quadrula tuberculata (Raf.) : Danglade (1914:9) Cyclonaias tuberculata granifera (Lea) : Baker (192a: 107) Rotundaria tuberculata Raf., 1820: Morrison (pers. comm., 4 January 1968) Danglade (1914:38) listed two spe- cies of purple warty-backs {Q. granifera and Q. tuberculata) as occurring in the Illinois River in 1912. Regarding grani- fera he stated (Ibid.) that: "This is a rather rare shell in the Illinois, although a few examples were found in the upper half of the shell-producing portion of the river at Chillicothe, Peoria, Havana, and Bath. It is an inflated shell, heavy anteriorly, and reaches a good size, but on account of its dull pur- ple nacre it is not now used for the manufacture of buttons." Danglade (1914:38) considered fufoer- culata as rare in the river and comment- ed that: "some examples of this mussel were found in the lower stretches of the river where the water is swifter, as below the Government locks at La Grange, at Diamond Island, and at Hardin. There appears to be a more or less gradual change from the in- flated granifera of the upper stretch- I es, where there is but little current and the bottom is composed largely of soft mud, to the much flatter tuberculata of the lower river where the bottom is harder and the cur- rent is stronger." Baker (1928:103-109) recognized three ecological forms of Cyclonaias tuberculata: (i) compressa, a flat shell found in small streams; (ii) tuberculata, a wider and more elongated shell than compressa occurring in medium-sized rivers like the upper Ohio and the Illi- nois; and (iii) granifera, which was smaller and wider and had higher um- bones and a more corpulent shell than tuberculata and which inhabited the large rivers, such as the Mississippi and the lower Illinois. Even though Baker (1928:109) mentioned that the form granifera occurred in the lower Illinois River, he (1928:108) stated that he had not seen this form from the river. Concerning this species in Indiana, Goodrich & van der Schalie (1944: 306) stated that: "In passing from the mid-portion of a large stream such as the Wa- bash into the region at and below Terre Haute one finds that this species has coarser pustules. For- merly the name granifera was ap- plied io the large-river phase of C. tuberculata. It is now known that granifera is merely an eco- logical form." This species was not taken alive in the 1966 survey of the Illinois River. Neither Morrison (pers. comm., 4 Jan- uary 1968) in the 1930's nor Parmalee (pers. comm., 21 November 1966) in the 1950's took a live specimen of this species in their collections from the river. Parmalee (Ibid.) did find several old shells of this species at Naples in 1955. In the period of 1896-1897, Kelly (1899: 401) examined 18 specimens of Q. tuberculata and a specimen of Q. grani- fera collected near Havana. Calkins Feb., 1971 Starrett: Mussels of the Illinois River 307 (1874:46) reported that the purple warty-back occurred in the upper river (Starved Rock pool). This species was not taken in the upper and middle river collections made in 1912 by Forbes & Richardson (1913). A specimen collected from the river at Havana in 1912 (INHS A-224) was identified by Stansbery (pers. comm., 20 July 1967) as the granifera (Lea, 1838) form of C. tuberculata. The few sub- fossil shells of this species taken in the 1966 survey between river miles 94.3 and 256.5 appeared to be less inflated than the aforementioned form granifera specimen. Morrison (pers. comm., 4 January 1968) referred to the U.S. Na- tional Museum specimens listed below from the river as Rotundaria tuberculata and made no mention of form. Like- wise, Parmalee (pers. comm., 21 Novem- ber 1966) listed the above mentioned dead shells he collected at Naples as Cyclonaias tuberculata. Because of the limited number of specimens examined during this study, the author agrees with Stansbery (pers. comm., 31 July 1968) that the purple warty-back should be referred to simply as Cyclonaias tuberculata. The host fish for the purple warty- back is not known. Museum Records. — Near Chicago (Calkins) USNM 25998; Chillicothe (1907 Freeland & Williams) USNM 676963 and 677041; and Havana (1912) INHS A-224. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— River mile 94.3, 219.4, 240.4, and 253.5- 256.5. OSM 18283, 18458, 18467, and 18479. Bullhead (Sheepnose) Plethobasus cyphyus (Rafinesque, 1820) Plethobasus cyphyus (Raf.) : Parmalee (1967:35; 1962:9) Unio Aesopus Green : Calkins (1874:41) Pleurobema aesopus Green: Baker (1906:77) Pleurobema aesopus (Green) : Danglade (1914:10) In the early 1870's Calkins (1874:41) found this species occurring abundantly in the Illinois River in La Salle County (Starved Rock pool). Baker (1906:77) reported that the bullhead mussel was collected at Havana. This species was not reported from the upper river in 1912 by Forbes & Richardson (1913). Danglade (1914:41) considered this spe- cies rare in the Illinois River in 1912, and he collected live specimens only at Bath and Meredosia. Regarding the bullhead, he stated: "It is brittle and not a good button shell; moreover, be- ing so uncommon in the Illinois, it is disregarded altogether." No live specimen of this species was taken in the 1966 survey. One subfossil shell was collected at river mile 94.3 (near Browning). Parmalee (pers. comm., 21 November 1966) found dead shells of this species in 1955 at Naples, but he took no live specimen of this ispecies in his collections during the 1950's. Likewise, Morrison (pers. comm., 27 November 1967) did not take a live bullhead mussel in his river collections in the early 1930's. Regarding the present status of this species in Illinois, Parmalee (1967:35) considered it to be restricted to the Mis- sissippi and Wabash rivers where it was generally uncommon to rare. Evidently by 1912 the bullhead was a rare species existing only in the lower part of the river. The museum records indicated that the species once occurred upstream as far as Morris (Marseilles pool). Because of these records and other evidence presented here, it ap- peared to the author that the bullhead formerly occurred throughout much of the river in limited numbers and in the upper river abundantly (Calkins 1874: 41). Evidently pollution and the reduc- tion in current caused by the dams eliminated this species from the river. The host fish for this species was be- lieved by Baker ( 1928 : 1 1 2 ) to have been the sauger. Museum Records. — Near Chicago ( "one very old example, perhaps 50 years old when collected" Calkins) USNM 84315; Morris (Shimek Coll.) USNM 515034; and Illinois River without local- ity (1870's) BK and ("including one example 40 years old" John Wolf, ex James Lewis) USNM 25987. 308 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Live Mussel Records ( 1966 Survey) .— None. Old Shell Records (1966 Survey).— River mile 94.3. OSM 18282. Pleurobema cordatum Complex Pleurobema cordatum (Raf.) : Parmalee (1967:35) van der Schalie (pers. comm., 31 August 1967) Unio coccineus Lea: Calkins (1874:42) Unis\o\ solidus Lea: Calkins (1874:45) Unio obliquus Lam.: Calkins (1874:44) Quadrula obliqua Lamarck: Baker (1906:80-81) Quadrula coccinea Conrad (= catillus Conrad) : Baker (1906:81) Quadrula solida Lea (= fulgidus Lea) : Baker (1906:81) Quadrula pyramidata Lea: Baker (1906:81) Quadrula pyramidata (Lea) : Danglade (1914:9) Quadrula plena (Lea) : Danglade (1914:9) Quadrula solida (Lea) : Danglade (1914:9) Quadrula coccinea (Con.) : Danglade (1914:9) Quadrula obliqua (Lam.) : Danglade (1914:9) Quadrula obliqua (Lamarck) : Coker (1921:25) Pleurobema plenum: Richardson (1928:458) Pleurobema catillus var. solida: Richardson (1928:458) Pleurobema catillus var. coccinea: Richardson (1928:458) Pleurobema cordatum: Richardson (1928:458) Pleurobema coccineum solida (Lea) : Baker (1928:118) Quadrula (Obliquata) catillus (Con- rad) : FMNH Quadrula (Obliquata) coccinea coccinea (Conrad) : FMNH Quadrula (Obliquata) obliquata (Raf.) : FMNH Pleurobema (cordatum) pyramidatum : Parmalee (1962:9) Pleurobema c. coccineum : Parmalee (1962:9) Danglade (1914:9 & 39) recognized five species of mussels of this complex occurring in the Illinois River in 1912, all of which he considered rare except Q. obliqua. About this species Danglade (1914:39) stated: "This shell, while not a common one in the Illinois, is found generally dis- tributed throughout the river. It furnishes good button material, but is hardly equal in size or quality to the species in the Ohio River beds." He (1914:37) did not record taking any species of this complex from the river above Peoria Lake. No live specimen belonging to this complex was taken in the 1966 survey of the Illinois River. Likewise, neither Parmalee (pers. comm., 21 November 1966) in the 1950's nor Morrison (pers. comm., 27 November 1967) in the 1930's collected any living specimens of this complex from the river. Calkins (1874:42, 44, & 45) reported that U. coccineus occurred abundantly in the Illinois River in La Salle County (Starved Rock pool). He also found -[/. obliquus in the river in association with U. solidus. Baker (1906:80-81) reported four species of this complex from the Illinois River. Coker (1921: 25) stated that Q. obliqua was found in the Illinois River. However, Baker (1928:137) did not find this species in the Hinkley and Daniels collections from the Illinois River. Pleurobema coccine- um solida was reported by Baker (1928: 120) as occurring in the Illinois. Van der Schalie (pers. comm., 31 Au- gust 1967) informed the author of two old records of Pleurobema cordatum (forma?) from the Illinois River in the collections of the University of Michi- gan Museum of Zoology. He wrote: "This species was studied by Ort- mann and he clearly indicated that the forms all belong to the central P. cordatum complex. It would simplify matters if the name Pleu- robema cordatum were used and then append the form names coc- cineum (small river form) and catil- COLOR PLATES Live Mussels Collected in the 1966 Survey of the IIKnois River PLATE I 1. Floater, Anodonta grandis grandis Say 2. Floater, Anodonta grandis corpulenta Cooper 3. Three-Ridge, Amblema plicata (Say) 4. Washboard, Megalonaias gigantea (Barnes) 5. Pimple-Back, Quadrula pustulosa (Lea) 6. Maple-Leaf, Quadrula quadrula (Raf.) PLATE 2 7. Warty-Back, Quadrula nodulata (Raf.) 8. Paper Pond Shell, Anodonta imbecillis Say 9. Fragile Heel-Splitter, Proptera laevissima (Lea) 10. Pink Heel-Splitter, Proptera alata (Say) 11. Fragile Paper Shell, Leptodea fragilis (Raf.) 12. White Heel-Splitter, Lasmigona complanata (Barnes) PLATE 3 13. Rock Pocketbook, Arcidens confragosus (Say) 14. Pig-Toe, Fusconaia flava forma undata (Barnes) 15. Three-Horned Warty-Back, Obliquaria reflexa Raf. 16. Slough Sand-Shell, Lampsilis anodontoides forma fallaciosa (Smith) 17. Fat Mucket, Lampsilis radiata luteola (Lamarck) 18. Ebony Shell, Fusconaia ebena (Lea) PLATE 4 19. Heel-Splitter, Anodonta suborbiculata Say 20. Hickory-Nut, Obovaria olivaria (Raf.) 21. Deer-Toe, Truncilla truncata Raf. 22. Fawn's Foot, Truncilla donaciformis (Lea) 23. Liliput Shell, Carunculina parva (Barnes) The color plates were printed before live specimens of the Buckhorn, Tritogonia verrucosa (Raf.), were collected from the Illinois River in 1969. PLATE 1 — Illinois River Mussels 11 PLATE 2 — Illinois River Mussels 13 14 15 16 17 18 PLATE 3 — Illinois River Mussels 19 21 20 22 23 PLATE 4 — Illinois River Mussels Feb., 1971 Starrett: Mussels of the Illinois River 309 lus or pyramidatum which really are the forms that occur in a large river like the Illinois. Most certainly there is no such species (following Ortmann) as Pleurobema pyrami- datum that should be listed as a separate entity." Relative to the P. cordatum complex in the Illinois River, Parmalee (pers. comm., 29 June 1967) stated: "I encountered dead shells (and have some in the collections) com- monly at Naples, 2 miles north of Meredosia and 3 miles S.E. of Ban- ner. This was undoubtedly a com- mon species in the Illinois River before pollution and silting. In my opinion and interpretation, cordat- um is the species and coccineum, catillus and pyramidatum are all subspecies or variants." The author examined several speci- mens belonging to this complex from the river at the Field Museum of Natural History. These specimens were cata- logued as to subspecies, and their re- spective museum numbers were listed later under Pleurobema cordatum com- plex. After conversing with Dr. David H. Stansbery about this complex, the author had no confidence in his own identifications of these museum speci- mens. Because of differences of opinion that existed among taxonomists concerning the nature of the P. cordatum complex, the author decided to use here only the scientific names applied to old shells of this complex collected in the 1966 sur- veys and to shell specimens from the river he submitted to Dr. Stansbery for identification. These specimens were de- posited in The Ohio State Museum. Stansbery (1967) recently has done ex- tensive work with this complex and has revised it into three described and one undescribed species. Stansbery (pers. comm., 31 July 1968) noted that he could not with clear conscience lump all the species of the P. cordatum com- plex under a single name, since he could demonstrate neither the existence of a cline nor the existence of intermediates connecting these species. This was in essential agreement with Baker (1928: 113-123). As a result of Dr. Stans- bery's identifications, the author has ac- cepted two species of this complex as once having occurred in the Illinois River: (i) Pleurobema coccineum forma solida (Lea, 1838) and (ii) Pleurobema pyramidatum (Lea, 1831). Museum specimens not checked by Dr. Stansbery have been listed below under P. cor- datum complex. Pleurobema coccineum forma solida (Lea, 1838) Museum Records. — Havana (1894) OSM 19232; Meredosia (1913) OSM 19231; and Illinois River without local- ity (1870's) OSM 5018. Live Mussel Records ( 1966 Survey). — None. Old Shell Records (1966 Survey).— River mile 44.9, 66.0, 196.3-198.1, and 219.4. OSM 18200, 18220, 18445, and 18459. Pleurobema pyramidatum (Lea, 1831) Museum Records.—Illinois River with- out locality (pre-1900) OSM 19230. Live Mussel Records ( 1966 Surrey). — None. Old Shell Records (1966 Survey).— None. Pleurobema cordatum Complex Museum Records. — Starved Rock (Frierson Coll.) UMMZ 79705; Can- ton [?] (pre-1943 Webb Coll.) FMNH 22694; 3 miles SE of Banner (1953 Parmalee) ISM 819 (dead) ; Havana (1895 Hay) FMNH 6439; and Illinois River without locality FMNH 14313 and (James Lewis) UMMZ 79667. Elephant's Ear Elliptio crassidens (Lamarck, 1819) Elliptio crassidens (Lamarck) : Parmalee (1967:29; 1962:9) Richardson (1928:458) Unio crassidens Lam. : Calkins (1874:42) Unio crassidens Lea: Baker (1906:77) Unio crassidens (Lea) : Danglade (1914:10) Parmalee (1962:9) listed 11 specimens of this species from the Kingston Lake Site middens (1100-1400 AD) located 310 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 adjacent to the Illinois River 15 miles southwest of Peoria. It was presumed that these specimens had been taken by the Indians from the river. Calkins (1874:42) considered the elephant's ear an abundant species in the Illinois River in La Salle County (Starved Rock pool) . This species was reported from the river at Utica by Baker ( 1 906 : 77 ) . Danglade (1914:37) collected this mussel from the Illinois River in 1912 at Chillicothe, Bath, Meredosia, Florence, Pearl, Kampsville, Diamond Island, Hardin, Twelve-Mile Island, and Grafton (possibly Mississippi River). Relative to the elephant's ear in the Illinois, Danglade (1914:41) noted : "Rare; although found in most of the beds, the percentage is so small that it is practically a negligible quantity. The nacre varies from pink to white. This shell is used for making novelties." The elephant's ear was not collected from the upper river in 1912 by Forbes & Richardson (1913). In the 1966 survey only two old shells of this species were collected and no live specimen was taken. Parmalee (pers. comm., 21 November 1966) collected dead shells of this species in 1955 at Naples. The elephant's ear was not taken from the river by Morrison (pers. comm., 27 November 1967) in the early 1930's. Formerly this species occurred in much of the Illinois River; however, except in the upper river it apparently was never abundant. It probably disappeared from the river before 1930. The host fish for the elephant's ear is not known. Museum Records. — Havana (1894 Baker) UIMNH 22172; and Meredosia (1913) INHS. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— River mile 129.8 and 156.0. OSM 18314 and 18363. Lady-Finger (Spike) Elliptic dilatatus (Rafinesque, 1820) Elliptio dilatatus (Raf.) : Parmalee (1967:29; 1962:9) Richardson (1928:457) MCZ Unio gibbosus Barnes: Calkins (1874:42) Kelly (1899:401) Forbes & Richardson (1913:536) Unio gibbosus Barnes (= arctior Lea) : Baker (1906:76-77) Unio gibbosus (Barnes) : Danglade (1914:10) Elliptic (Eurynia) dilatatus dilatatus (Raf.) : FMNH Elliptio dilatatus Raf., 1820: Morrison (pers. comm., 4 January 1968) Calkins (1874:42) collected this species from the river in La Salle County (Starved Rock pool) in the early 1870's. In the period of 1896-1897, Kelly (1899: 401) examined 25 specimens of lady- fingers collected in the Havana area. In 1912 Forbes & Richardson (1913:535 & 536) did not collect this species any farther upstream than Henry. Danglade (1914:37) reported taking this mussel in 1912 at all of his principal collecting stations in the river between Henry and Grafton. However, by 1925 Richardson (1928:454-457) found that pollution had destroyed this species in the upper river above Lower Peoria I^ake. Concerning this species in the Illinois River Danglade (1914:41-42) wrote: "The lady-finger is not now a com- mercial shell unless it be white, which is seldom the case. It is found in large quantities along the river, some beds, which the clammers avoid as much as possible, having a very large percentage. Above the upper bridge at Peoria there are two small beds of this species; one bed consists mostly of white nacred shells, while in the other the nacre is the ordinary dull purple color. At Meredosia a driveway leading from the river to the bank above is covered with about 60 tons of these shells. They had been purchased at a low price in the hope that there would be a demand for them. Button cutters claim that even the white gibbosus do not make good blanks on account of the shell being brittle." Morrison (pers. comm., 27 November 1967) did not collect this species at Meredosia in 1930, whereas 20 years Feb., 1971 Starrett; Mussels of the Illinois River 311 earlier it apparently was abundant in that area, as indicated by Danglade. In 1955 Parmalee (pers. comm., 21 November 1966) collected only dead shells of this species at Naples, Meredosia, and near Banner. No live specimen of this species was taken in the 1966 survey, but dead shells were collected at various points along the river. The lady-finger formerly was an abun- dant mussel found throughout most of the river. The species probably was elimi- nated by pollution and siltation between 1925 and 1955. The fish host of the lady-finger is not known. Museum Records.—Spring Bay Nar- rows (1912 Danglade) USNM 678600; Peoria Narrows (1924) INHS 1-F; Peoria Lake (pre-1910) MCZ; Peoria (1870's) BK; Havana (1894 Baker) UIMNH 22174 and (1912) INHS A-33; Grand Island (1912 Danglade) USNM 678601 ; Naples (1955 Parmalee) ISM 1156-1157 (dead); 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678563 and (1907 Bartsch stat. 109) USNM 678564; and Illinois River without locality (pre- 1943 Webb Coll.) FMNH 22017 and (pre-1910) MCZ. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— River mile 44.9, 66.0-66.4, 75.8, 94.3, 106.8, 129.8, 145.7, 156.0, 167.2, 184.5, 219.4, and 253.5-256.5. OSM 18199, 18221, 18255, 18284, 18295, 18315, 18333, 18364, 18378, 18384, 18460, and 18481. Pond-Horn Uniomerus tetralasmus (Say, 1830) Uniomerus tetralasmus (Say) : Parmalee (1967:44) Unio tetralasmus Say (= jamesianus Lea): Baker (1906:77) In the collection of the University of Illinois Museum of Natural History the author examined a specimen of this spe- cies collected at Havana by Baker in 1894. However, the label did not specify Illinois River. Baker ( 1 906 : 7 7 ) did not mention this record from Havana but did state that this species had been collected from Phelps Lake, Fulton County. Relative to Phelps Lake, Kofoid (1903:414-415) noted : "This body of water lies on the western side of the river about a mile below the city of Havana, in the elevated bottom-lands below the mouth of Spoon River. ... At river stages of 1 1 ft. and above, backwater from Spoon River makes its way through a now abandoned channel to the lake and thence out to the river through the slough." The river Kofoid referred to was the Illinois River. Phelps Lake was drained and leveed off for agricultural purposes about 60 years ago. The author is of the opinion that the UIMNH specimen labeled Havana was the record referred to by Baker as from Phelps Lake. No other record or specimen of this species from the river and its adjoining bottomland lakes was located by the author. Museum Records. — Havana ( 1 894 Baker) UIMNH 22147. Live Mussel Records ( 1966 Survey). — None. Old Shell Records (1966 Survey).— None. Lastena lata (Rafinesque, 1820) Lastena lata (Rafinesque) : Parmalee (1967:87) Lastena lata Rafinesque {— dehiscens Say) : Baker (1906:73) Baker (1906:73) reported that Marsh collected this species from the Illinois River. This is the only report known to the author of this species having been found in this river. Goodrich & van der Schalie (1944:308) considered this a rare shell throughout its range. Accord- ing to Stansbery (pers. comm., 31 July 1968) : "A review of the literature and museum collections reveals this spe- cies as restricted to the Ohio River drainage system. It would not be expected from the Illinois River. It is apparently absent from all of its range except the Green River of the Kentucky and the Clinch River of the Southern Appalachians." In the author's opinion the record by Baker should be considered doubtful. 312 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Museum Records-—None. Live Mussel Records ( 1966 Survey). — None. Old Shell Records (1966 Survey).— None. Subfamily ANODONTINAE (Rafinesque, 1820) Ortmann, 1910 Rock Pocketbook Arcidens confragosus (Say, 1829) (Plate 3-13) Arcidens confragosus (Say) : Parmalee (1967:51; 1962:9) Danglade (1914:10) MCZ Alasmodonta confragosa Say: Kelly (1899:401) Forbes & Richardson (1913:533) Arcidens confragosus Say: Baker (1906:74) Morrison (pers. comm., 4 January 1968) Arcidens confragosa (Say) : FMNH Seventy-five live specimens of this spe- cies were taken in the 1966 survey of the Illinois River (Table A-3). The rpck pocketbook constituted 1.8 percent of the live mussels taken and ranked sixth in abundance (Tables 6 and 7) . In the 1966 collections 77.3 percent of all live speci- mens of this species were taken in the Alton pool. Only one live specimen was collected in the Peoria pool. As indicated in Table A-3, the rock pocketbook was not taken in the Peoria-Pekin area nor upstream from Middle Peoria Lake, which indicated that it was not as tolerant of pollution as some other species. Sub- fossil shells were collected in 1966 as far upstream as river mile 219.4 (near Spring Valley) . A few specimens of this mussel were observed in sorted commercial shell piles at Meredosia and Kampsville. In the 1966 survey 26.6 percent of the rock pocketbooks taken alive were 2.5 inches or more in height and 77.3 percent were 7-11 years of age (Table A- 19). This species was not abundant enough to be of commercial importance. Calkins (1847:46) did not mention that he had collected this species (Mar- garitana confragosa Say) in the river (Starved Rock pool). However, Baker (1906:74) reported that a specimen of Arcidens was collected at Utica, only a short distance downstream from Starved Rock. In 1912 Forbes & Richardson (1913:533) took this species upstream as far as Hennepin. According to Danglade (1914:37 & 42), the rock pocketbook was found on almost all of the mussel beds that he inspected between Henry and Grafton. He regarded this mussel as not particularly useful as a button shell. Evidently this species formerly was found upstream as far as Utica and was limited by pollution in the 1920's to approximately its present distribution in the river. The host fish for this mussel is not known. Museum Records.—Peru (pre- 19 10) MCZ; between Peoria and Pekin (1908 Freeland & Williams) USNM 677291; Liverpool (pre- 1900 Strode) FMNH 9243; Quiver Lake (1894 Baker) UIMNH 22161, (1899) INHS A-99, and (1955 Parmalee) ISM 1054-1066; Ha- vana (Hay) FMNH 13938, (1910Zetek) FMNH 68169, and (1912) INHS A-140; Frederick (pre- 1943 Webb Coll.) FMNH 21646; Meredosia (1930 Morrison) USNM 678629-678630, (pre-1910) MCZ, and (1955 Parmalee) ISM 1392- 1393; Naples (1955 Parmalee) ISM 1096-1098; Pearl (1907 F & W) FMNH 11253 and (1965 Parmalee) ISM 3300- 3303; 1 mile below Hardin (1907 Bartsch Stat. 108) USNM 678551; and 10 miles below Hardin (1907 Bartsch stat. 110) USNM 678552. Live Mussel Records ( 1966 Survey). — River mile 0.9-1.0 (LB), 10.3-10.5 (RB), 14.9-15.1 (RB), 19.2-19.4 (RB), 24.2-24.4 (LB), 28.9-29.1 (RB), 39.1- 39.3 (RB), 40.3-40.5 (RB), 42.2-42.3 (LB), 45.4-45.9 (LB), 48.3 (RB), 51.0- 51.3 (RB), 51.2 (LB), 53.8 (LB), 54.3 (RB), 56.3 (LB), 57.5-57.7 (LB), 60.8 (RB) , 64.4 (LB) , 75.8 (RB) , 86.4 (LB) , 86.6 (LB), 86.8 (LB), 87.9 (LB), 106.7 (LB), 110.0 (RB), 110.5 (RB), 122.0 (LB), 129.8-130.4 (RB), 132.0 (LB), and 167.5-167.7 (LB). OSM 17700- 17703, 17704 (2), 17710, 17716, 17717, Feb., 1971 Starrett: Mussels of the Illinois River 313 and 17719; FMNH 156985 (2), 156986 (2) , 156988 (4) , 157003 (4) , and 157006 (9). Old Shell Records (1966 Survey).— River mile 44.9, 75.8, Quiver Lake, 129.8, 156.0, and 219.4. OSM 18201, 18256, 18304, 18316, 18365, and 18461. Fluted Shell Lasmigona costata (Rafinesque, 18201 Lasmigona costata (Rafinesque) : Parmalee (1967:53) Margaritana rugosa Barnes: Calkins (1874:46) Symphynota costata Rafinesque (= rugo- sa Barnes) : Baker (1906:74) Symphynota costata (Raf.) : Danglade (1914:10) According to Baker (1928:143) the fluted shell occurred in both large and small rivers and had a preference for gravel on riffles but also lived in sand and fine gravel in quiet waters. In the early 1870's the Illinois River in the vicinity of Starved Rock had a sandy bottom which supported a large mussel popula- tion (Calkins 1874:11). Calkins (1874: 46) reported that the fluted shell occurred abundantly there (Starved Rock pool) in the early 1870's, and from the nearby Fox River (a tributary stream of the Illi- nois) he collected a specimen (USNM 58168) which was deposited at the U.S. National Museum (Morrison, pers. comm., 14 June 1968). Baker (1906:74) reported that both Handwerk and Strode had collected this species from the river. The last reported record of the fluted shell from the Illinois known by the author was that of a single specimen taken at Bath by Danglade (1914:42) in 1912. The author was unable to locate a museum specimen of this species from the Illinois. Van der Schalie (pers. comm., 31 August 1967) and Parmalee (pers. comm., 29 June 1967) were of the opinion that the fluted shell could have occurred in the Illinois River. Stans- bery (pers. comm., 31 July 1968) in- formed the author that he would have expected this species to have occurred in the upper reaches of the Illinois before the river was impounded. Morrison (pers. comm., 4 January 1968) had this to say about the fluted shell: "Uncommon in the Wisconsin and Rock Rivers; if ever living in the main Illinois River, it must have been in the neighborhood of the Kankakee, before being polluted out." In 1924 Morrison (Ibid.) collected a living specimen from the Kankakee River at Wilmington (USNM 678623) and a dead shell from the Des Plaines River at Des Plaines (USNM 678624) in 1932. The author examined a fluted shell taken by Hinkley (UIMNH 14801) from the Des Plaines River. The confluence of the Des Plaines and Kankakee rivers is only about 40 miles upstream from where Calkins (1874:46) found the fluted .shell occurring abundantly in the early 1870's. In the author's opinion the citations presented above indicate that the fluted shell formerly occurred in the Illinois River. Pollution probably eliminated this mussel from the upper river, possibly even before the completion of the Chicago Sanitary and Ship Canal in 1900. The host fish for the fluted shell is not known. Museum Records.—None. Live Mussel Records (1966 Survey). — None. Old Shell Records (1966 Survey).— None. Lasmigona compressa (Lea, 1829) Lasmigona compressa (Lea) : Parmalee (1967:52) Symphynota compressa Lea (= pressa Lea) : Baker (1906:74) Baker (1906:74) reported that Hand- werk collected this species in the Illinois River. This was the only record of this species from the Illinois known to the author, and he was unable to locate a museum record to substantiate it. This species, according to Baker ( 1928: 141), was found in creeks, in small streams, and far up into the headwaters of rivers. Morrison (pers. comm., 27 314 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 November 1967) and Stansbery (pers. comm., 31 July 1968) were of the opinion that compressa probably never had oc- curred in the Illinois River but rather in its tributary streams. The author believed that Handwerk's specimen probably was collected either in or near the mouth of a tributary stream of the Illinois rather than from the river proper. Museum Records.—None. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. White Heel-Splitter Lasmigona complanata (Barnes, 1823) (Plate 2-12) Lasmigona complanata (Barnes) : Parmalee (1967:52) Richardson (1928:457) MCZ Margaritana complanata Barnes: Calkins (1874:46) Alasmodonta complanata Bar.: Kelly (1899:401) Symphynota complanata Barnes: Baker (1906:75) Forbes & Richardson (1913:529) Symphynota complanata (Barnes) : Danglade (1914:10) Calkins (1874:46) considered this mus- sel abundant in the Illinois River in La Salle County (Starved Rock pool) . In the 1896-1897 period, Kelly (1899:401) examined 1 1 specimens from the Havana area. Danglade (1914:42) considered this mussel fairly common in the Illinois River. In 1912 Forbes & Richardson (1913:528-533) collected specimens up- stream as far as Starved Rock, and they took 23 live white heel-splitters at Hen- nepin in that year. Richardson (1928:456-457) found in the mid-1920's that the upstream range of this species in the Illinois River had been reduced considerably since 1912 as a result of pollution. He took no live specimen above the lower end of Upper Peoria Lake. This was approximately the location (river mile 168.5) where the last li\e specimen of this species was taken in the 1966 survey. In 1966 only 13 live white heel-splitters were taken from the entire river (Table A-3) . This species ranked 14th in abun- dance, based on the total number of live mussels taken (Tables 6 and 7), and it constituted 0.3 percent of the total catch (Table A-3). This species had no im- portance as a commercial shell from the Illinois River in 1966. Morrison (pers. comm., 27 November 1967) did not collect this species at Meredosia in 1930. However, in 1957 Parmalee (pers. comm., 21 November 1966) took a live specimen at Liverpool (river mile 128.0) and in 1965 another at Pearl (river mile 43.0). In 1955 he did not find live specimens of this species at Naples or Mededosia (Alton pool). Evidently, the upstream distribution of the white heel-splitter has been limited by pollution since the 1920's to about the lower end of Upper Peoria Lake. This mussel apparently was much more abun- dant before 1913 than it was in 1966. The fish host of the white heel-splitter is not known. Museum Records.—Peru (pre- 1910) MCZ; Liverpool (1957 Parmalee) ISM 2255; Quiver Lake (1955 Parmalee) ISM 1039 (dead); Havana (1909) INHS and (1912) INHS a-208; Naples (1955 Parmalee) ISM 1118 (dead) ; and Pearl (1965 Parmalee) ISM 3299. Live Mussel Records ( 1966 Survey). — River mile 14.9-15.1 (RB), 64.4 (LB), 68.6 (RB), 110.1 (LB), 122.0 (LB), 129.8-130.4 (RB), 145.7 (RB), 148.5 (LB), 161.1-161.3 (LB), 165.3-166.1 (RB), and 168.1-168.5 (RB) . OSM 17724; FMNH 156961 and 156998. Old Shell Records (1966 Survey).— River mile 129.8 and 156.0. OSM 18317 and 18366. Floater Anodonta grandis Complex Anodonta grandis Say: Parmalee (1967:47; pers. comm., 21 November 1966) Forbes & Richardson (1913:533) Feb, 1971 Starrett: Mussels of the Illinois River 315 Anodonta ovata Lea: (Calkins 1874:47) Anodonta grandis Say (= salmonia Lea, ovata Lea) : Baker (1906:72-73) Anodonta grandis (Say) : Danglade (1914:10) Anodonta grandis var. gigantea: Richardson (1928:457) Anodonta (Pyganodon) grandis Say : Morrison (pers. comm, 4 January 1968) Anodonta (Anodonta) grandis grandis: FMNH Anodonta corpulcnta Cooper: Parmalee (1967:47; pers. comm, 21 November 1966) Calkins (1874:47) Strode (1891fl: 133-134) Kelly (1899:401) Baker (1906:73) Forbes & Richardson (1913:525) Richardson (1928:457) Anodonta corpulenta (Cooper) : Danglade (1914:10) Anodonta (Pyganodon) corpulenta Cooper : Morrison (pers. comm., 4 January 1968) One hundred twenty live specimens belonging to this complex were taken from the Illinois River in the 1966 sur- vey. The author was unable to identify the species of many of the specimens in this collection. At the suggestion of Dr. David Stansbery the entire collection was submitted to him for study and identification. Dr. Stansbery's analysis of this material (pers. comm., 12 Sep- tember 1967) follows: "The relationship of Anodonta grandis Say, 1829, to many of the other Anodonta 'species' of North America is unknown. Clarke (1966) has recently studied the Anodonta cataracta complex of central and eastern Canada and has concluded that all of the described forms of this complex in the east are reduc- ible to one species having but two subspecies. The Anodonta grandis forms of central Canada, he con- cludes, are all reducible to a single species having but two subspecies (represented in Canada). The task now remams to deal \vith the rela- tively few forms of this complex presently recognized in the Missis- sippi River drainage of central North America. Once accomplish- ed, this should set the stage for dealing with the east and west Gulf Coast (stream) faunas and the low- er Atlantic Coast fauna of this com- plex. "Simpson (1914) placed most of the grandis-\\ke forms described from the Mississippi River drainage into the synonymy of A. grandis. Most students of the naiads have been content to let them remain so. Only the Anodonta forms of the lakes and big rivers have persisted in the literature into the present as separate species and/or subspecies depending on the author. Baker (1928) was the last author to deal with the big-river Anodonta forms in any detail. He recognized Ano- donta grandis Say, 1829, Anodonta gigantea Lea, 1834, and Anodonta corpulenta Cooper, 1834, as sep- arate species. These are the only three forms of the complex with which we are concerned in identi- fying the Illinois River specimens. "Simpson (1914:420) concludes that gigantea Lea is a variety of A. grarz^zj and Baker (1928:163) notes that 'Apparently the only sure way of separating grandis from gigantea is by an examination of the glo- chidia.' These observations supple- mented by a careful examination of the material in the OSM collections lead me to conclude that gigantea is most probably the environmental form of A. grandis in large rivers. It is larger, more compressed, has a straighter ventral margin, (all relative intergrading characters) and larger glochidia. This latter character (size of glochidia) is the only distinct difference and its dis- 316 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 tinctness may well be due to lack of data from populations which are geographically intermediate. "Although Anodonta corpulenta is also known from large rivers or their bayous (as is A. g. gigantea) , until I examined the Illinois River specimens I saw no cause for con- fusing the two. Baker (1928:169) notes that A. corpulenta 'may be at once known from grandis gigantea, which it most nearly resembles, by its large corpulent shell, alate dor- sal margin, on both sides of the um- bones, its swollen umbones, and its nodulous beak sculpture. It is a squarish shell, the height being al- most equal to the length. The glo- chidia are also different, . . . .' To these characters I would only add that the nacre is usually a coppery- pink and that the umbonal swelling is best described as mammae-form. "The Illinois River material (120 specimens) of this complex here un- der study consists of 1 19 measurable specimens and one so badly dam- aged that its dimensions could not be taken. These specimens consti- tute 47 lots. The dimensions of length, width and height were tak- en from each specimen and the height index, width index, and transverse index were calculated for all specimens as well as for the types where possible (i.e., no width is given by Cooper (1855) for the type of A. corpulenta). "In height index the type of A. grandis (HI = 67) is 5% greater than the type of A. gigantea (HI = 62) but only 5% less than the type of A. corpulenta. In width in- dex the type of A. grandis (WI = 44) is 1% greater than the type of A. gigantea (WI = 43). Neither can be compared with the same proportion of the type of A. corpu- lenta since no width dimension or figure of the type was given by Cooper. One is led to believe from the descriptions that A. corpulenta is the widest or most corpulent of the complex. Cooper noted that his species is 'much inflated at the umbones, . . . .' Marsh (1887:36) says A. corpulenta is 'very much in- flated . . . .' Simpson (1914:430) observes this species 'with excessively full and high beaks, the wide um- bonal swelling extending down on the disk . . . .' and Baker (1928: 169) comments on 'its large corpu- lent shell ... .' in comparing it with A. grandis and A. gigantea. "Marsh (1887:36) in his paper on the shells of Mercer County, Illinois, reveals a broader concept of A. corpulenta than most. He states at the close of his description of that species that 'Although cor- pulenta is generally very much in- flated, specimens are often found that are much depressed.' (The un- derlining is mine.) Earlier Marsh (1887:21) wrote, 'Grandis is the type of a number of . . . very close- ly allied species, . . . . Typical forms of these species are easily sep- arated when once well known, but intermediate forms are so extremely puzzling that no conchologist can separate them to a certainty.' My respect for Marsh has increased markedly since studying the material from the Illinois River! "Having concluded that A. gigan- tea is most probably an environmen- tal form of A. grandis we are left with the relationship between A. grandis (and its many forms) with A. corpulenta. The Illinois River specimens have a width index ex- tending from a low of 35 to a high of 51 with a mean of 41.5. This mean is slightly less than the mean of the types of A. grandis and A. gigantea. Thus A. corpu- lenta appears corpulent not be- cause the shell is wider than A. grandis or A. gigantea but because the shell is narrower both anterior and posterior to the central swell- ing. I therefore conclude that the Feb., 1971 Starrett: Mussels of the Illinois River 317 width index cannot be used to separate A. corpulenta from the others. "An examination of all of our material of this complex leads me to conclude that A. corpulenta is characterized by : 1 ) having a peculiar expan- sion of the umbonal region usually extending to the very beaks, which can best be termed mammae-form. 2) a nacre which is copper- pink. 3) a greater height index than related forms. "Two of these characters (1 and 3) seem to intergrade by imper- ceptible degrees with A. grandis which lacks the mammae-form umbones, is more elongate, and rarely (if ever—never in my ex- perience) has a copper-pink nacre. This intergradation seems, at the present time to be limited to the Illinois River material. Material from the Mississippi River and the lower Tennessee River does not intergrade with A. grandis. We have very few specimens of A. corpulenta from the Tennessee River, however, and none which fit the description of A. grandis. "The fact that A. corpulenta is not simply an environmental form of A. grandis has been dramatical- ly demonstrated here in Ohio. Un- til 1966 there were no Ohio rec- ords for this species. A draw-down of Cowan Lake, an impoundment of Cowan Creek, revealed an ex- tremely large population of A. cor- pulenta. This is especially note- worthy since Ohio has many such impoundments in which are found populations of A. grandis or no naiads at all. Although A. imbecil- lis is present in Cowan Lake, A. grandis seems to be completely ab- sent. I believe this to be expected if there are no intrinsic reproduc- tive barriers between the two forms. One would expect the few A. grandis specimens present in Cowan Creek to have either been eliminated by the new environ- ment or absorbed by the A. corpu- lenta population. Introductions of bait fishes from the west and else- where have been and are being made in Cowan Lake allowing ample opportunity for the introduc- tion of naiad species as encysted glochidia. "It appears that, under certain conditions, A. corpulenta and A. grandis can and do live in the same habitat and may intergrade. The Illinois River seems to be just such a situation. Here we find A. corpu- lenta as the common form but ac- companied by specimens which de- viate in nacre color, height index, and umbonal swelling. Of the 119 specimens studied 101 were A. cor- pulenta in every respect. Fourteen of the 18 additional specimens ex- hibited mixed characters and are interpreted as intergrades. Only 4 specimens possessed all the charac- ters of Anodonta grandis. In view of this evidence, I believe it best to treat corpulenta Cooper, 1834, as a subspecies of grandis Say, 1829. Hence : Anodonta grandis grandis Say, 1829. —a subspecies of ponds, lakes, and all but the largest rivers. Anodonta grandis corpulenta Cooper, 1834. —a subspecies of the bayous and ponded parts of our largest rivers until recently. Now turning up in im- poundments as it has ac- cess to this newly formed favorable habitat." The author has accepted Dr. Stans- bery's opinion that corpulenta should be treated here as a subspecies of grandis. Since the classification of this complex has been modified here, the author be- 318 Illinois Natural History Survey Bullktin Vol. 30, Art. 5 lieved that it would be more accurate to list the synonymies of names used by other collectors of grandis and corpu- lenta from the Illinois River under the heading of Anodonta grandis complex rather than to attempt to allocate them to subspecies. The museum records from the Illinois River have been treated sim- ilarly. The old records of A. grandis from the river were more questionable, in the author's opinion, than those of A. corpulenta. Possibly some of the A. grandis specimens reported from the riv- er were intergrades between grandis and corpulenta, as was the case with 14 of the specimens taken in the 1966 survey. Calkins (1874:47) reported collecting A. ovata and A. corpulenta from the Illinois in La Salle County in the early 1870's (Starved Rock pool). At Ottawa in 1912 Forbes & Richardson (1913: 525 & 533) collected a specimen of A. corpulenta which "had quite recently suc- cumbed, the flesh being not yet decayed." At Hennepin in that year they took 14 live specimens of A. corpulenta and 1 dead A. grandis. Richardson (1928:456- 457) found that the distribution of A. corpulenta had been reduced, as a result of pollution, from as far upstream as Spring Valley in 1912 to no farther up than the lower end of Upper Peoria Lake in the 1924-1925 period. In that period he did not collect_i4. grandis var. gigantea from Peoria Lake. Strode (1891a: 134) found A. corpulenta occurring abun- dantly in the shallow waters of Thomp- son Lake (now drained and leveed off from the Illinois River) near Havana. In the early 1930's Morrison (pars, comm., 4 January 1968) collected A. (P.) grandis and A. {P.) corpulenta at Meredosia. Concerning floaters {Anodonta) in the Illinois, Danglade (1914:42) stated that: "They are thin, paperlike shells and have no commercial or economic value, excepting perhaps as they are used occasionally by the mussel fish- ermen for fish bait or hog feed" Museum Records.— (Referred to as .4. grandis) Between Peoria and Pekin (1908 Freeland & Williams) USNM 678589; between Pekin and Havana ( 1907 F & W) USNM 677058; Liverpool (1957 Parmalee) ISM 2256 and 2367-2369; Quiver Lake (1955 Parmalee) ISM 1022-1027; Lake Chautauqua (1952) FMNH 54890 and 54898; Thompson Lake (pre-1900 Strode) FMNH 67959; Havana (1894 Baker) UIMNH 22168; Meredosia (1932 Morrison) USNM 678627 and (1955 Parmalee) ISM 1371- 1372; Naples (1955 Parmalee) ISM 1099-1102; and Illinois River without locality (1895 Hay) FMNH 6515, (pre- 1900 Strode) FMNH 9252, (pre-1943 Webb Coll.) FMNH 21633, and (pre- 1910) MCZ. (Referred to as A. corpulenta) Thomp- son Lake (pre-1900 Strode) FMNH 9251 and 9256 and UIMNH 15038; back- water slough 1 mile W of Havana ( 1953 Parmalee) ISM 269; Havana (1912) INHS A- 145; Meredosia (1930 Morri- son) USNM 678628; and Illinois River without locality UIMNH 7366. (Referred to as possible A. corpulenta) Quiver Lake (1955 Parmalee) ISM 1028. Anodonta grandis grandis Say, 1819 (Plate 1-1) Only four live specimens of grandis were taken in the 1966 survey of the Illinois (Table A-3). All of these mus- sels were collected in the La Grange and Peoria pools between river miles 100.0 and 196.1, including one specimen from Quiver Lake. In the author's opinion this subspecies was never as abundant in the Illinois River and its bottomland lakes as corpulenta. According to Parmalee (1967:100), the host fishes for A. grandis are the carp, Cyprinus carpio Linnaeus, yellow perch, bluegill, rock bass, and white crappie. All of these fishes are common in the Illinois River proper except the rock bass and yellow perch. Museum Records.—Utica (pre-1900) OSM 9085; and Illinois River without locality (pre-1900) OSM 10403. Live Mussel Records ( 1966 Survey) . — River mile 100.0-100.5 (LB), Quiver Lake (LB), 167.2 (RB),and 196.1 (LB). Feb, 1971 Starrett: Mussels of the Illinois Ri\er 319 OSM 17430, 17435, 17447, and 17461. Old Shell Records (1966 Survey).— None. .\nodonta grandis corpulenta Cooper, 1834 (Plate 1-2) The corpulenta subspecies was distrib- uted throughout the lower three navi- gation pools of the Illinois River in 1966 (Table A-3) ; 116 live specimens were taken. Corpulenta ranked fifth in abundance in the 1966 collections of live mussels from the entire river, and in the Peoria pool it ranked second in abun- dance (Tables 6 and 7). The occurrence of corpulenta in the upper parts of the La Grange and Peoria pools indicated that it was one of the species more tolerant of pollution than other mussels. The reports and records on the A. grandis complex presented above indicated that corpulenta formerly occurred upstream at least as far as Ottawa and that by the 1920's its up- stream distribution had been reduced considerably by pollution. The 1966 sur- vey data indicated that this mussel now occurs farther upstream than it did in the 1920's, as reported by Richardson (1928:456-457). Baker (1928: 169) states that the skip- jack is the host fish for corpulenta. The author is of the opinion that perhaps some other kind or kinds of fishes be- sides the skipjack serve as hosts for this mussel. This opinion is based on the fact that the skipjack is uncommon in the Illinois River, whereas corpulenta is common and widely distributed in the lower three navigation pools. Museum Records.—Utica (pre- 1900) OSM 9086; and Illinois River without locality (pre- 1900) OSM 10397 and 23992 (dead). Live Mussel Records ( 1966 Survey). — River mile 1.0 (LB), 5.4-5.5 (RB), 13.0 (RB), 13.2-13.5 (LB), 14.9-15.1 (RB), 29.0 (RB), 30.6 (RB), 53.6 (LB), 66.0- 66.4 (LB), 68.6 (RB), 75.8 (RB), 86.8 (LB), 106.7 (LB), 110.0 (RB), 115.5 (RB), 122.0 (LB), 129.8-130.4 (RB), 143.7 (RB), 145.7 (RB), 147.7 (RB), 148.5 (LB), 155.9-156.4 (RB), 161.2 (RB), 161.7-161.8 (LB), 162.3 (RB), 162.3 (LB), 164.4-165.1 (LB), 164.5- 164.9 (RB), 166.6 (LB), 167.5-167.7 (LB), 168.1-168.5 (RB), 168.2 (RB), 169.3 (RB), 169.5 (LB), 170.5-170.9 (LB), 170.9 (RB), 174.1 (LB), 174.9 (LB), 191.5 (LB), 196.1 (LB), 198.1 (RB), and 229.3 (LB). OSM 17417 (5), 17418 (7), 17419 (6), 17420-17425, 17426 (11), 17427, 17428 (2), 17429, 17431 (3), 17432-17434, 17436 (10), 17437, 17438 (4), 17439 (3), 17440- 17442, 17443 (2), 17444, 17445, 17446 (2), 17448 (2), 17449 (9), 17450, 17451 (2), 17452 (4), 17453 (7), 17454 (2), 17455 (2), 17456, 17457 (4), 17458 (2), 17459 (/a), 17460, 17461 (3), 17462, and 17463. Old Shell Records (1966 Survey).— River mile Meredosia Lake, 66.0-66.4, 75.8, 86.6-86.8, Lake Alatanzas, Quiver Lake, 129.8, 156.0, and 184.5. OSM 18263, 18274, 18367, and 18383. Paper Pond Shell Anodonta imbecillis Say, 1829 (Plate 2-8) Anodonta imbecillis Say: Parmalee (1967:48) Calkins (1874:47) Baker (1906:72) Forbes & Richardson (1913:533) Richardson (1928:457) MCZ Anodonta imhecilis Say: Kelly (1899:401) Anodonta imbicillis (Say) : Danglade (1914:10) Anodonta imbecillis (Say) : Danglade (1914:43) Anodonta (Anodonta) imhecilis Say: Morrison (pers. comm., 4 January 1968) Regarding the paper pond shell in the Illinois River, Danglade (1914:43) stated: "This small, delicate shell is very abundantly distributed, especially in the more retired places of quiet waters." However, he indicated (1914:37) that this shell was taken only at three of his principal stations (Peoria Lake, Havana, and Bath). Calkins (1874:47) reported 320 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 collecting this mussel in La Salle County (Starved Rock pool) in the early 1870's, but in 1912 Forbes & Richardson (1913: 533) found it occurring upstream only as far as Hennepin. By the mid-1920's Richardson (1928:457) found that its upstream range was limited to the lower end of Upper Peoria Lake as a result of pollution. Kelly (1899:401) exam- ined 47 specimens of this mussel from the river at Havana in the 1896-1897 period, and in 1930 Morrison (pers. comm., 4 January 1968) collected it at Meredosia. In the 1966 survey ony five live paper pond shells were collected at four differ- ent sites between river miles 30.6 and 198.1 (above Henry) (Table A-3). These specimens were collected by wad- ing and with the dredge; they were 4—7 years of age. This species was apparently less abundant in the Illinois River in 1966 than it was before 1913; however, it had moved upstream since the mid- 1920's. The fish host for this mussel is Lepomis sp. (Parmalee 1967:100). Museum Records.—Peru (pre- 1910) MCZ; Depue Lake (1918 Baker) UIMNH 10982; Mossville (1924) INHS G-5-A; Peoria Lake (1931 Baker) UIMNH 31487 and 31531-31532; Quiv- er Lake (1955 Parmalee) ISM 1030 and 1038; and Merdeosia (1930 Morrison) USNM 678625-678626. Live Mussel Records ( 1966 Survey) . — River mile 30.6 (RB), 66.0-66.4 (LB), 129.8-130.4 (RB), and 198.1 (RB). OSM 17743 and 18021. Old Shell Records (1966 Survey).— None. Heel-Splitter Anodonta suborbiculata Say, 1831 (Plate 4-19) Anodonta suborbiculata Say: Parmalee (1967:48) Strode (1891a: 133) Baker (1906:72) Richardson (1928:457) Anodonta suborbiculata (Say) : Danglade (1914:10) Anodonta [Utterbackiana) suborbiculata (Say) : FMNH In 1890 at Thompson Lake (now drained and leveed off from the river) near Havana, Strode (1891a: 133-134) noted : "In some places the bottom of the lake seemed to be literally paved with the suborbiculata. With a six- tined potato-digger I would some- times bring up five or six at a haul; and if the fishermen happened to be making a draw with the great seine, a half barrel of them would sometimes be drawn out at once . . ." Danglade (1914:37 & 43) collected the heel-splitter from the river at Peoria Lake, Havana, Bath, and Bedford. He mentioned that it was widely distributed in the Illinois and was generally found on mud bottoms in slack water. In the 1924-1925 period Richardson (1928: 457) reported taking this mussel in Mid- dle Peoria Lake. In 1953 Parmalee (pers. comm., 21 November 1966) found the heel-splitter occurring commonly in a mud slough backwater area of the Illinois River near Havana. In the 1966 survey suborbiculata was not taken from the river proper; how- ever, one living specimen was collected from Lake Matanzas, a river bottomland lake located south of Havana. The host fish for this mussel is not known. Museum Records.—Mossville (1924) INHS E-5a; Thompson Lake (pre-1900 Strode) FMNH 2574, 9254, 50232, and 68176 and (Hinkley) UIMNH 4709; Havana (1894) INHS and (1894 Baker) UIMNH 22162; 1 mile W of Havana in a backwater slough of the Illinois River (1953 Parmalee) ISM 61-63, 89, and 260. Live Mussel Records ( 1966 Survey) . — Lake Matanzas (LB). OSM 17723. Old Shell Records (1966 Survey).— None. Slipper-Shell m| Alasmidonta calceolus (Lea, 1829) ^t\ Alasmidonta calceolus (Lea) : Parmalee (1967:44) Baker (1928:187) Margaritana deltoidea Lea: Calkins (1874:46) Alasmidonta viridis Rafinesque, 1820: Morrison (pers. comm., 14 June 1968) This small-stream species was reported Feb., 1971 Starrett: Mussels of the Illinois River 321 by Calkins (1874:46) as occurring in the Illinois River. This report was cor- roborated by Dr. Morrison (pers. comm., 14 June 1968), who wrote that he had examined in the collections of the U.S. National Museum a specimen of Alasmi- donta viridis Rafinesque collected from the Illinois River by Calkins. He men- tioned that the specimen was labelled "deltoidea." Neither Baker (1906) nor Danglade (1914) reported the slipper- shell from the Illinois. However, at a later date Baker (1928:187) stated that this species did occur in the Illinois, but he made no mention of locality or collector. Apparently this species former- ly occurred only in limited numbers in the upper river and was eliminated from the river about 1900 by pollution. The host fish for the slipper-shell is not known. Museum Records.—Illinois River with- out locality (1870's Calkins) USNM 26047. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. Elk-Toe Alasmidonta marginata Say, 1818 Alasmidonta marginata (Say) : Parmalee (1967:45; 1962:9) Margaritana marginata Say: Calkins (1874:4&-47) Alasmidonta marginata Say: Baker (1906:75) Morrison (pers. comm., 14 June 1968) Alasmidonta [Decurambis) marginata (Say) : FMNH According to Calkins (1874:46-47) the elk-toe occurred abundantly in the upper river in the early 1870's. Baker (1906:75) reported than Handwerk also had collected this species from the river. Parmalee (1962:7 & 9) found the elk-toe in the Kingston Lake Site middens along the Illinois River (15 miles SW of Pe- oria) ; however, he thought that the finding of this headwater or small-stream species was unusual, since all other mus- sel specimens at the site \vere large-river species. Dr. Morrison (pers. comm., 14 June 1968) mentioned that in the col- lections of the U.S. National Museum are specimens of this species taken before 1900 from the Illinois River at Morris and Peoria. The author was unable to find any record of the elk-toe from the Illinois after the turn of the century. Apparently this species formerly occurred only in the upper and middle parts of the Illi- nois and was eliminated by pollution fol- lowing the opening of the Chicago Sani- tary and Ship Canal in 1900. The host fish of the elk-toe is not known. Museum Records.—Morris (pre- 1900 Shimek Coll.) USNM 504536; Peoria (1875 Lewis) USNM 86177; and Illinois River without locality (pre- 1943 Webb Coll.) FMNH 21703. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. Squaw Foot Strophitus undulatus (Say, 1817) Strophitus rugosus (Swainson) : Parmalee (1967:56) Baker (1928:201) Strophitus edentulus Lea: Kelly (1899:401) Forbes & Richardson (1913:530 & 533) Strophitus edentulus Say (= shafjeriana Lea, wardiana Lea) : Baker (1906:71) Strophitus edentulus (Say) : Danglade (1914:10) Strophitus undulatus (Say) : Morrison (pers. comm., 4 January 1968) Danglade (1914:43) reported that the squaw foot was: "Found rather scatter- ing throughout the various stretches and mussel beds of the river." He (1914:37) collected this mussel at Peoria Lake, Pekin, Bath, Florence, and Hardin. In 1912 Forbes & Richardson (1913:530 & 533) collected a dead shell of this mussel in the La Salle-Peru area and a live specimen at Hennepin. Neither Morri- son (pers. comm., 4 January 1968) in the early 1930's nor Parmalee (pers. comm., 29 June 1967) in the 1950's took the squaw foot in the Illinois River. The squaw foot was not taken in the 322 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 1966 Illinois River survey; however, a live specimen (OSM 18183, identified by Dr. Stansbery as Strophitus undulatus .Say, 1817)^ was collected in 1966 from the Aux Sable River, a tributary stream of the Illinois. This species was evidently never com- mon in the Illinois River and it probably disappeared from the river before 1930. According to Baker (1928:201), the glochidia of this mussel have experi- mentally gone through metamorphosis on the fins and skin of the largemouth bass and the creek chub, Semotilus atromacu- latus (Mitchill). Both of these fishes occur in the Illinois River. Museum Records.—Havana (Smith) UMMZ 74648 and (1894 Baker) UIMNH 22170; 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678553; Illinois River without locality ( 1907 Free- land & Williams) USNM 678590 and INHS. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. Cylindrical Paper Shell Anodontoides ferussacianus (Lea, 1834) Anodontoides ferussacianus (Lea) : Parmalee (1967:51) MCZ Anodontoides ferrussacianus [sic]: Forbes & Richardson (1913:533) Anodontoides jerrusacianus [sic]: Richardson (1928:457) "This small, rather fragile, thin- shelled mussel is found mainly in the northern third of the state [Illi- nois], living in small, quiet streams, on a sand or fine gravel bottom in shallow water" (Parmalee 1967:51). Forbes & Richardson (1913:533) re- ported collecting a live specimen of this species from the Illinois River at Henne- ' stansbery (pers. comm.. 20 July 1967) stated: "The reason that S. undulatus (Say, 1817) has S. rugoBus (Swainson, 1822) as a synonym is because: '* ( 1 ) No one has ever been able to demonstrate that there are indeed two species (one eastern in New York, New England, etc.. and one Miss, drain- age) and "(2) Strophitus undulatus (Say) has five years' priority as the name of this species. Clarke and Berg (1969:43-44) recognized the conspecificity of undulatus Say and rucinaus Swainson in their study of the naiads of upper New York." pin in 1912. Two unmatched valves of this species taken from the river at Peru (pre- 19 10) were deposited in the Mu- seum of Comparative Zoology. Dr. Stansbery (pers. comm., 20 January 1970) checked these shells for the author and found them to be typical Anodon- toides ferussacianus. This small-stream species was not col- lected in the 1966 survey of the river. The paucity of records for this species from the Illinois indicated that its oc- currence there was probably accidental even before 1900. The host fish of this mussel is not known. Museum Records.—Peru (pre-1910) MCZ 70919. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. Subfamily LAMPSILINAE (von Ihering, 1901) Ortmann, 1910 Three-Homed Warty-Back Obliquaria reflexa Rafinesque, 1820 (Plate 3-15) Obliquaria reflexa Rafinesque: Parmalee (1967:77) Kelly (1899:401) Forbes & Richardson (1913:536) Richardson (1928:457) Morrison (pers. comm., 4 January 1968) Unio cornutus Barnes: Calkins (1874:41) Obliquaria reflexa Rafinesque (=cornuta Barnes): Baker (1906:71) Obliquaria reflexa (Raf.) : Danglade (1914:10) According to Danglade (1914:43): "This mussel is widely distributed and is usually of small size. There are two or three forms of reflexa found in the Illinois. In the upper stretches of the river it is of the ordinary shape and size found in other streams, and although it can be used for manufacturing purposes it is not a particularly valuable shell to propagate. In the Peoria Lake region, however, where the current Feb., 1971 Starrett: Mussels of the Illinois River 323 is slow and the bottom is composed of soft mud, the shell is often very heavy and rounded anteriorly, while posteriorly it is thin and much elon- gated, which no doubt is the result of accommodation to natural con- ditions. In the lower stretches the shell, though heavy and inflated, is considerably smaller than those in the upper portions of the river." In the early 1870's Calkins (1874:41) collected O. reflexa from the river in La Salle County (Starved Rock pool). Forbes & Richardson (1913:536) took this mussel as far upstream as the Henry- Chillicothe section in 1912. However, by the mid-1920's the range of this spe- cies extended upstream only to Middle Peoria Lake as a result of pollution (Rich- ardson 1928:456-457). In 1912 Dan- glade (1914:37) collected the three- horned warty-back at Chillicothe, Peoria Lake, and at most of his other principal stations downstream. In the 1966 survey the three-horned warty-back was taken alive from the river proper only in the Alton pool between river miles 0.9 and 75.8 (Table A-3 ) . A single live specimen was taken by wading in the La Grange pool at Quiver Lake just above Havana. This species ranked seventh in abundance in the Alton pool and tenth in the entire river (Tables 6 and 7). The shell heights ranged from 0.9 to 1.6 inches; these shells were therefore too small to have any commercial importance in the pearl-culture industry. The 49 live three- horned warty-backs taken in the 1966 survey ranged from 4 to 15 years in age, but 87.8 percent of these mussels were 6-11 years old (Table A-20). Since the early 1870's the range of the three-horned warty-back has been greatly reduced as a result of pollution, and this mussel now occurs only in the lower navigation pool of the river proper. The fish host of the three-horned warty-back is not known. Museum Records.—Peoria Narrows (1924) INHS 1-J; Peoria, above bridge (1912 Danglade) USNM 678604; Quiv- er Lake (1955 Parmalee) ISM 1050- 1052; Havana (1894 Baker) UIMNH 22165-22166, (1895 Hay) FMNH 14892, and (1912) INHS a-138; Mercdosia (1930 Morrison) USNM 678650 and (1955 Parmalee) ISM 1366-1370; Na- ples (1955 Parmalee) ISM 1124-1129; 1 mile below Hardin ( 1907 Bartsch stai. 108) USNM 678568; 10 miles below Hardin (1907 Bartsch stat. 110) USNM 678569; 2 miles above Grafton (1907 Bartsch stat. Ill) USNM 678570; and Illinois River without locality FMNH 22863 and 22873. Live Mussel Records ( 1966 Survey). — River mile 0.9-1.0 (LB), 5.5 (RB), 10.5 (RB), 14.9-15.1 (RB), 21.7-22.0 (RB), 29.0 (RB), 40.3-40.5 (RB), 42.3 (LB), 45.4-45.9 (LB), 51.2 (LB), 54.3 (RB), 54.4 (RB), 58.0 (RB), 62.6 (RB), 64.4 (LB), 69.0 (RB),72.9 (RB), 75.8 (RB), 79.8 ( RB ) , and Quiver Lake ( LB ) . OSM 18017 and 18019; FMNH 156946, 156949, 156967, 156968, 156976 (2), 156990, and 156991 (4). Old Shell Records (1966 Survey).— River mile 15.0, 44.9, 66.0-66.4, 75.8, 156.0, 196.1, and 219.4. OSM 18202^ 18208, 18222, 18257, 18368, 18434, and 18462. Hickory-Nut Obovaria olivaria (Rafinesque, 1820) (Plate 4-20) Obovaria olivaria (Rafinesque) : Parmalee (1967:78; 1962:9) OSM Unio ellipsis Lea : Calkins (1874:42) Lampsilis ellipsis Lea: Kelly (1899:401) Obovaria ellipsis Lea: Baker (1906:69) Obovaria ellipsis (Lea) : Danglade (1914:10) One live specimen of the hickory-nut was taken in the 1966 survey with the exploratory crowfoot bar on a hard mud bottom in 11.3 feet of water at river mile 1 .0. This specimen was 1 1 years of age and its shell height was 2.0 inches. In the early 1870's Calkins (1874:42) reported that this species occurred abun- dantly in the Illinois River in La Salle County (Starved Rock pool). In the 1896-1897 period Kelly (1899:401) ex- 324 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 amined three specimens of this species taken from the river in the Havana area. Baker (1906:69) mentioned that Handwerk collected the hickory-nut in the Illinois. Danglade (1914:44) con- sidered this species comparatively rare in the river in 1912. At that time he (1914:37 & 44) took a few hickory-nuts at Peoria Lake, Florence, Bedford, Pearl, Kampsville, Hardin, Twelve-Mile Island, and Grafton (possibly Mississippi River). This species was not taken by Morri- son (pars, comm., 4 January 1968) at Meredosia in the early 1930's. He com- mented that : "in 1931 at Fairport, Iowa, in the Mississippi River, this species was almost completely replacing Sintoxia antrosa [ebena] behind the wing dams on that river." In the present study only one live speci- men of each of these two species was taken from the Illinois River, and both of these records were from near the mouth of the river where it empties into the Mississippi River. According to Parmalee (1967:78) the hickory-nut occurs: "usually on a sand or gravel bottom in good current." Silta- tion and pollution probably have been the factors which have virtually elimi- nated the hickory-nut from the river. The host fish for the hickory-nut is not known. Museum Records.—Starved Rock (pre- 1900) OSM 10214; Peoria (1870's) BK; and Calhoun County (1928 Baker) UIMNH 27286. Live Mussel Records ( 1966 Survey).— • River mile 1.0 (LB). OSM 18014. Old Shell Records (1966 Survey).— None. Obovaria retusa (Lamarck, 1819) Obovaria retusa (Lamarck) : Parmalee (1967:94) Unio retusus Lam. : Calkins (1874:44) Obovaria retusa Lamarck: Baker (1906:69) Calkins (1874:44) and Strode (Baker 1906:69) both supposedly collected this species from the Illinois River. However, the author was unable to locate any other records of this mussel's having been taken from the Illinois. Concern- ing this species in Illinois, Parmalee (1967:78) stated: "Obovaria retusa . . . formerly oc- curred in the lower Wabash and Ohio rivers, but it has apparently now disappeared from these rivers." Because of the lack of substantial evi- dence of the occurrence of this species in the Illinois River, the author consid- ered the above reports of retusa doubt- ful. Museum Records.—None. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. Mucket Actinonaias ligamentina (Lamarck, 1819) Actinonaias carinata (Barnes) : Parmalee (1967:56; 1962:9) MCZ Actinonais [sic] carinata: Richardson (1928:457) Unio ligamentinus Lam.: Calkins (1874:43) Lampsilis ligamentinus Lam.: Kelly (1899:401) Lampsilis ligamentina : Forbes & Richardson (1913:529) Lampsilis ligamentina Lamarck [=crassa Say) : Baker (1906:65) Lampsilis ligamentina (Lam.) : Danglade (1914:10) Actinonaias ligamentina Lamarck, 1819: Morrison (pers. comm., 4 January 1968) OSM No live muckets were taken in the 1966 survey; however, old shells of this species were collected at various points along the entire Illinois River from river mile 44.9 to mile 256.5. In the early 1870's Calkins (1874:43) found this mussel occurring abundantly in the upper river (Starved Rock pool). In 1912 Forbes & Richardson (1913:529) took I Feb., 1971 Starrett: Mussels of the Illinois River 325 living muckets as far upstream as the La Salle-Peru area. Richardson (1928: 456-457) reported that by the mid-1920's pollution had eliminated this species from the river, at least from Peoria up. Before the turn of the century the mucket was common in the Havana area, as evidenced by Kelly's (1899:401) re- port of examining 24 specimens col- lected from that part of the river in the 1896-1897 period. In 1912 Danglade (1914:37) collected this species at all of his principal collecting stations be- tween Henry and Grafton with the ex- ception of Meredosia. He (1914:46) found the mucket occurring in small numbers throughout the river but more abundantly in Peoria Lake than else- where. Neither Morrison in the early 1930's (pers. comm., 4 January 1968) nor Parmalee in the 1950's (pers. comm., 21 November 1966) collected this spe- cies from the river. Apparently pollution and siltation had eliminated this formerly widely distrib- uted mussel in the Illinois River before 1930. According to Baker (1928:220) the host fishes for the mucket are : green sun- fish; bluegill; smallmouth bass, Microp- terus dolomieui Lacepede; largemouth bass; yellow perch; white crappie; and white bass. All of these fishes still occur in the Illinois River. Museum Records.—Peru (pre- 19 10) MCZ; Peoria (pre-1900) OSM 10232; between Pekin and Havana (pre-1910) MCZ; Havana (1894 Baker) UIMNH 22152 and (1912) INHS A-174; 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678571 and (1907 Bartsch stat. 109) USNM 678572; and Illinois River stat. K, (1908 Freeland & Williams) USNM 678605. Live Mussel Records ( 1966 Survey). — None. Old Shell Records (1966 Survey).— River mile 44.9, 94.3, 106.8, 129.8, 145.7, 156.0, 196.3-198.1, 219.4, 240.4, and 253.5-256.5. OSM 18205, 18286, 18296, 18318, 18334, 18370, 18464, 18465, 18468, and 18482. Butterfly Plagiola lineolata (Rafinesque, 1820) Plagiola lineolata (Rafinesque) : Parmalee (1967:80-81; 1962:9) Richardson (1928:457) MCZ Plagiola securis Lea: Kelly (1899:401) Baker (1906:69) Forbes & Richardson (1913:536) Plagiola securis (Lea) : Danglade (1914:10) Plagiolopsis lineolata (Raf.) : FMNH Ellipsaria lineolata Rafinesque, 1820: Morrison (pers. comm., 4 January 1968) Concerning this species in the Illinois River, Danglade (1914:44) stated: "The butterfly, or securis, is not a common species in this river, al- though many of the beds could be made to yield productively by propa- gation. On account of its flatter shape and proportionally lighter weight, the male shell is more valu- able for commercial purposes than the female." Danglade (1914:37) reported that this species occurred at all of his principal collecting stations except Henry, Bed- ford, and Spar Island. In 1912 Forbes & Richardson (1913:536) collected the butterfly in the Henry-Chillicothe sec- tion of the river; however, in the mid- 1920's this species was not taken in Pe- oria Lake by Richardson (1928:457). Kelly (1899:401) examined five speci- mens of this mussel collected in the Havana area. The butterfly was not taken alive in the 1966 survey, nor was it taken by Morrison (pers. comm., 4 January 1968) in the early 1930's nor Parmalee in the 1950's. The literature citations, museum records, and old shell records included here indicated that the butterfly formerly occurred throughout much of the river, but this mussel probably had disappeared by the mid-1920's. Parmalee (1967:81) stated that: "Plagiola is apparently less tolerant 326 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 of silting and pollution than many species; it was once fairly common and widespread in the Illinois River, but has now completely disappeared as a result of these factors." The fish host for the butterfly mussel is the freshwater drum, Aplodinotus grunnzV/iJ- Rafinesque, (Baker 1928:232) still a common fish in the Illinois River. Museum Records. — Starved Rock FMNH 59280; La Salle (Baker) UIMNH 14073; Peru (pre-1910) MCZ; Peoria (1912) INHS; Fulton County (pre- 1900 Strode) FMNH 9217; Havana (1912) INHS; Meredosia (1913) INHS and (pre-1910) MCZ; 1 mile below Har- din (1907 Bartsch stat. 108) USNM 678573; and Illinois River without lo- cality ( 1879 Hinkley) UIMNH 4499 and (1870's) BK. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— River mile 44.9, 156.0, and 219.4. OSM 18204, 18369, and 18463. Deer-Toe Truncilla truncata Rafinesque, 1820 (Plate 4-21) Truncilla truncata Rafinesque: Parmalee (1967:86) Richardson (1928:457) MCZ Unio elegans Lea: Calkins (1874:42) Plagiola elegans Lea: Kelly (1899:401) Baker (1906:70) Forbes & Richardson (1913:536) Plagiola elegans (Lea) : Danglade (1914:10) Truncilla vermiculata Rafinesque, 1820: Morrison (pers. comm., 4 January 1968) Truncilla truncata (Raf.) : FMNH Danglade (1914:37 & 44) found the deer-toe in small quantities in 1912 at all but three of his principal stations be- tween Henry and Grafton. In the early 1870's Calkins (1874:42) took this spe- cies in La Salle County (Starved Rock pool). Forbes & Richardson (1913:536) collected the deer-toe in 1912 upstream as far as the Henry-Chillicothe section. Richardson ( 1928 : 456-^57 ) reported that by the mid-1920's pollution had eliminated this species from Peoria north. In the 1896-1897 period, Kelly (1899: 401) examined 25 deer-toes collected in the Havana area. In the 1966 survey 10 live deer-toes were taken between river miles 1.0 and 106.7. All but two of these specimens were collected in the Alton pool (Table A-3) . The deer-toe ranked 15th in abun- dance in the 1966 survey (Tables 6 and 7 ) . The heights of the shells of this species ranged from 0.9 to 1.3 inches. Danglade (1914:44) reported that in 1912 he examined a deer-toe from the Illinois which had a shell length of 2.75 inches, \vhereas the largest shell of this species taken in 1966 had a length of only 2.2 inches, too small to be of com- mercial value. The deer-toes collected in the 1966 survey ranged from 5 to 9 years in age. Evidently pollution has eliminated the deer-toe from the river proper above river mile 106.7. The fish host of the deer-toe is not known. Museum Records. — La Salle (pre- 1910) MCZ; Peru (pre-1910) MCZ; Peoria, above bridge (1912 Danglade) USNM 678606; Peoria (1913) USNM 678607; Quiver Lake (1955 Parmalee) ISM 1048; Havana (1894 Baker) UIMNH 22167, (1895 Hay) FMNH 6483, (1912) INHS a-122, and (1912) USNM 678608; Bath (1912) USNM 678609; Grand Island near Bath (1912 Danglade) USNM 678611; Meredosia (1912) USNM 678610, (1930 Morrison) USNM 678651, and (1955 Parmalee) ISM 1385-1386; Naples (1955 Parma- lee) ISM 1145-1151; Diamond Island, Dark Chute (1912 Danglade) USNM 678487 ; Hardin (1912 Danglade) USNM 678612; 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678574; and Illinois River without locality (1870's) BK. Live Mussel Records ( 1966 Survey V — River mile 1.0 (LB), 64.4 (LB),' 72.9 (RB), 75.8 (RB), 100.0-100.5 (LB), Feb., 1971 Starrett: Mussels of the Illinois River 327 and 106.7 (LB). OSM 18015 and 18020; FMNH 156969 (2). Old Shell Records (1966 Survey).— River mile 15.0, 44.9, 66.0-66.4, 75.8, 94.3, and Quiver Lake. OSM 18203, 18209, 18223, 18285, and 18305. Fawn's Foot Truncilla donaciforniis (Lea, 1828) (Plate 4-22) Truncilla donaciformis (Lea) : Parmalee (1967:85) OSM Unio zigzag Lea: Calkins (1874:46) Plagiola donaciformis Lea: Kelly (1899:401) Plagiola donaciformis Lea {=zigzag Lea) : Baker (1906:70) Plagiola donaciformis (Lea) : Danglade (1914:10) Truncilla {Amygdalonaias) donaciformis Lea: Morrison (pers. comm., 4 January 1968) Danglade (1914:43) considered this small mussel very common in the Illinois although he (1914:37) collected it at only about one-half of his principal sta- tions between Henry and Grafton. The museum records indicate that this species once occurred in much of the river be- tween Starved Rock and Grafton. This species was not collected from the Illinois River in 1912 between Morris and Chilli- cothe by Forbes & Richardson (1913). The farthest upstream the fawn's foot was taken by Danglade (1914:37) in 1912 was Peoria Lake. In 1930 Morrison (pers. comm., 4 January 1968) took this species at Mere- dosia. Parmalee (pers. comm., 21 No- vember 1966) in 1955 found the fawn's foot occurring commonly at Naples, Meredosia, and Quiver Lake. In the 1966 survey only one live specimen of this species was taken, and that was collected by wading at Naples. This species probably was too small to be taken with either the crowfoot bar or the dredge; however, if the species had occurred commonly in the river in 1966 It would have been taken regularly in the wading collections. Evidently by 1912 pollution had elim- inated this mussel from the river above Peoria Lake, and by 1966 it had been drastically affected in the lower river. It apparently occurs now only in small numbers in the Alton navigation pool of the river proper. The freshwater drum is the usual host fish for the fawn's foot (Baker 1928: 230), and this fish still occurs in the river. Museum Records.—Starved Rock (pre- 1900) OSM 10250 and (pre-1923 Fer- riss) FMNH 59226; Utica (pre-1923 Ferriss) FMNH 59246; La Salle (Hink- ley) UIMNH 14994; Peoria, above bridge ( 1912 Danglade) USNM 678613; Quiver Lake (1955 Parmalee) ISM 1040-1047: Havana (1894 Baker) UIMNH 22169 and (1912) INKS a- 167; Lake Matanzas UIMNH 4542; Meredosia Lake (1909) UIMNH 4523; Meredosia (1930 Morrison) USNM 678652-678653 and (1955 Parmalee) ISM 1387-1391; Naples (1955 Parma- ,lee) ISM 1152-1155; 1 mile N of Hardin ( 1956 Parmalee) ISM 2206 (dead) ; and 2 miles above Grafton (1907 Bartsch Stat. Ill) USNM 678575. Live Mussel Records ( 1966 Survey). — River mile 66.0-66.4 (LB). OSM 18018. Old Shell Records (1966 Survey).— River mile 15.0 and Quiver Lake. OSM 18210 and 18306. Fragile Paper Shell Leptodea fragilis (Rafinesque, 1820) (Plate 2-11) Leptodea fragilis (Rafinesque) : Parmalee (1967:72) MCZ Unio gracilis Barnes: Calkins (1874:42) Lampsilis gracilis Bar. : Kelly' (1899:401) Forbes & Richardson (1913:529) Baker (1906:68) Lampsilis gracilis (Barnes) : Danglade (1914:10) Lampsilis [Leptodea) fragilis (Raf.) : FMNH 328 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Leptodea fragilis Raf. : Baker (1928:234) Richardson (1928:457) Morrison (pers. comm., 4 January 1968) The fragile paper shell was widely distributed in the lower three navigation pools of the Illinois River in 1966, and 64 live specimens were taken between river miles 1.0 and 229.0 (Table A-3). It ranked eighth in abundance in 1966 (Tables 6 and 7). The shells ranged from 1 to 13 years of age. The 1 -year-old shell was taken in the Alton pool and had a height of 0.3 inch. Shells of this spe- cies were too thin to be of any com- mercial value. In the 1870's Calkins (1874:42) col- lected this mussel in La Salle County (Starved Rock pool). In the 1896-1897 period Kelly (1899:401) e.xamined 40 specimens of this species collected in the Havana area. Danglade (1914:37) found the fragile paper shell occurring at all of his principal stations between Henry and Grafton except at Valley City, Bed- ford, and Six-Mile Island. Forbes & Richardson (1913:529) in 1912 collected this species upstream as far as the La Salle-Peru area. By the 1920's pollution had reduced this mussel's upstream range to Middle Peoria Lake (Richardson 1928:457). As indicated above, in 1966 live specimens of the fragile paper shell were taken at river mile 229.0 (above La Salle), farther upstream than it was taken in 1912 by Forbes & Richardson. The apparent reestablishment of this species upstream since 1912 and the mid-1920's indicated that it was capable of adapting to pollution more success- fully than most of the mussels known to have occurred in the Illinois River and that pollution was less severe than it was in the 1920's. It was also one of the few mussel species able to survive the pollution in the Peoria-Pekin section of the river. The host fish for the fragile paper shell is not known. Museum Records.—Peru (pre- 1910) MCZ; between Peoria and Pekin (1908 Freeland & Williams) USNM 678614; Pekin (1907 F & W) FMNH 11224; between Pekin and Havana (1907 F & W) USNM 677057 and (pre-1910) MCZ; Liverpool (1957 Parmalee) ISM 2257-2259; Clear Lake (1894 Baker) UIMNH 22156; Quiver Lake (1894 Baker) UIMNH 22157 and (1955 Par- malee) ISM 1031-1033; 1 mile W of Havana, backwater slough (1953 Par- malee) ISM 88; Havana (1895 Hay) FMNH 14909 and (1912) INHS A-92; Meredosia (1930 Morrison) USNM 678654 and (1955 Parmalee) ISM 1373-1379; Naples (1955 Parmalee) ISM 1103-1108; 1 mile N of Hardin (1956 Parmalee) ISM 2196-2199 (dead); 10 miles below Hardin (1907 Bartsch stat. 110) USNM 678576; and Calhoun County (1928 Baker) UIMNH 27290. I Live Mussel Records ( 1966 Survey) .— ^ River mile 1.0 (LB), 5.5 (RB), 10.3- 10.5 (RB), 13.2-13.5 (LB), 14.9-15.1 (RB), 28.9-29.1 (RB), 47.4-47.7 (LB), 53.6 (LB), 56.3 (LB), 58.0 (RB), 60.8 (RB), 62.4 (RB), 62.6 (LB), 64.4 (LB), 66.0-66.4 (LB), 66.5 (LB), 66.9 (RB), 69.0 (RB), 72.9 (RB), 75.8 (RB),79.8 (RB),93.6 (LB), 95.8 (LB), 96.8 (RB), 98.0 (LB), 99.0-99.5 (RB), 100.0-100.5 (LB), 106.7 (LB), 108.8- 109.0 (RB), 110.1 (LB), 110.5 (RB), 113.2-114.0 (LB), 115.3 (RB), 115.5 (RB), 122.6-123.0 (LB), 145.7 (RB), 154.3-154.5 (RB), 159.4 (LB), 166.6 (LB), 167.5-167.7 (LB), 199.3 (RB), and 229.0 (RB). OSM 17708, 17712 (2), 17722, 17726, 17746, and 17750 (2); FMNH 156979 (5), 156981 (2), M 156984 (4), and 156989 (4). M Old Shell Records (1966 Survey).— * River mile 15.0, 129.8, 156.0, 184.5, and 196.3-198.1. OSM 18211, 18319, 18371, 18387, and 18446. Leptodea leptodon (Rafinesquc, 1820) Leptodea leptodon (Rafinesque) : Parmalee (1967:92) Lampsilis leptodon Rafinesque {=tniuusuna Lea) : Baker (1906:69) Baker (1906:69) reported that Fer- riss collected this species in the Illinois River. No other record of leptodon from the Illinois was located. Van der Schalie Feb., 1971 Starrett: Mussels of the Illinois River 329 (pers. comm., 31 August 1967) believed it doubtful that this mussel ever oc- curred in the Illinois. Parmalee ( 1967 : 92) listed leptodon as a species of doubt- ful occurrence in Illinois, and he made no mention of its ever having lived in the Illinois River. According to Stans- bery (pers. comm., 31 July 1968) : "Recent collection records show this species to exist in relic populations in Oklahoma, Arkansas, Missouri, and Kentucky. It may be extirpated from the rest of its former range. Despite its extensive former range, its former presence in the Illinois River (substantiated only by a sin- gle literature record unsupported by a museum specimen) is doubtful." The author was of the opinion that the above record of leptodon being tak- en from the Illinois River should be considered as doubtful. Museum Records.—None. Live Mussel Records ( 1966 Survey). — None. Old Shell Records (1966 Survey).— None. Pink Heel-Splitter Proptera alata (Say, 1817) (Plate 2-10) Proptera alata (Say) : Parmalee (1967:81; 1962:9) Richardson (1928:457) FMNH MCZ Lampsilis alatus Say : Kelly (1899:401) Lampsilis alata Say: Baker (1906:68) Forbes & Richardson (1913:529) Lampsilis alata (Say) : Danglade (1914:10) Potamilus alata megapterus Rafinesque, 1820: Morrison (pers. comm., 4 January 1968) Potamilus alatus: OSM The extreme upstream records from the Illinois River of this species known to the author were a single specimen taken in the La Salle-Peru section by Forbes & Richardson (1913:529-530) in 1912 and the pre-1910 MCZ collec- tions. Danglade (1914:37 & 44) con- sidered alata fairly common, and he re- ported taking it at most of his principal stations between Henry and Grafton. In the 1896-1897 period Kelly (1899:401) examined 38 specimens collected in- the vicinity of Havana. Richardson (1928:456-457) reported that by the mid-1920's pollution had eliminated the pink heel-splitter from the river above the Peoria Narrows. Of this species, 16 live specimens were taken from the Illinois River in the 1966 survey between river miles 1.0 and 196.1 (at Henry). The pink heel-splitter rank- ed 13th in abundance (Tables 6 and 7). The shell age determinations indicated that these specimens ranged from 9 to 17 years. This mussel had no value as a commercial shell in 1966. The presence of the pink heel-splitter in the Peoria- Pekin area indicated that this species was one of the more tolerant mussels to pollution; this mussel had extended its range upstream since the mid-1920's from the Peoria Narrows to Henry. How- ever, it evidently was unable to tolerate existing pollution conditions upstream as far as the La Salle-Peru aiea where it had been taken in 1912 by Forbes & Richardson. The decrease in the abundance of this species in the river since 1912 ap- parently was caused by pollution. The host fish for the pink heel-split- ter is not known. Museum Records.—Peru (pre-1910) MCZ; Peoria Narrows (1925) INHS J-1; Havana (1895 Hay) FMNH 6500, (pre- 1900 Strode) UIMNH 15175, and (1912 Danglade) USNM 678615; Mere- dosia (1955 Parmalee) ISM 1382-1384; Naples (1955 Parmalee) ISM 1119- 1121; 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678577 and ( 1907 Bartsch stat. 109) USNM 678578; Calhoun County (1928 Baker) UIMNH 27295; and Illinois River without local- ity (pre-1900) OSM 14593. Live Mussel Records ( 1966 Survey) . — River mile 1.0 (LB), 13.0 (RB), 13.2- 13.5 (LB), 47.5 (LB), 53.8 (LB), 57.6 (RB), 60.8 (RB), 75.8 (RB), 154.4- 330 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 154.5 (RB), 159.7-160.0 (RB), 161.2 (RB), and 196.1 (LB). OSM 17694 and 17744; FMNH 156962-156964, 156978, 156995, and 156996. Old Shell Records (1966 Survey).— River mile 15.0, 66.0-66.4, 75.8, Quiver Lake, and 184.5. OSM 18212, 18225, 18258, 18307, and 18385. Fat Pocketbook Proptera capax (Green, 1832) Proptera capax (Green) : Parmalee (1967:83) Unio capax Green: Calkins (1874:41) Lampsilis capax (Green) : Danglade (1914:10) Potamilus capax : OSM Relative to the, fat pocketbook, Dan- glade (1914:46) wrote: "This is a rare species in the Illinois, and was found more frequently be- low locks and dams where the water was swifter." Danglade (1914:37) did not take this species in 1912 between Henry and Pe- oria Lake; however, he did collect it at eleven of his principal stations between Pekin and Grafton. Calkins (1874:41- 42) reported taking capax in La Salle County (Starved Rock pool) in the ear- ly 1870's. One museum specimen of this species from the river was examined by the author and another was checked by Dr. Stansbery (pers. comm., 22 Decem- ber 1969). This species probably disappeared from the upper river by 1900 and from the middle and lower river before 1920. The fish host for this mussel is not known. Museum Records.—Illinois River with- out locality INHS and (pre-1900) OSM 4474. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. Fragile Heel-Splitter Proptera laevissima (Lea, 1829) (Plate 2-9) Leptodea laevissima (Lea) : Parmalee (1967:74) Richardson (1928:457) Lampsilis laevissimus Lea: Kelly (1899:401) Lampsilis laevissima Lea (= ohioensis Say) : Baker (1906:68) Forbes & Richardson (1913: 525 & 533) Proptera laevissima (Lea) : FMNH Lampsilis laevissima (Lea) : Danglade (1914:10) Potamilus ohiensis Rafinesque, 1820: Morrison (pers. comm., 4 January 1968) Baker (1906:68) reported that the fragile heel-splitter was collected from the river at Utica and at other locations downstream. Danglade (1914:37 & 44) considered this mussel fairly common in the Illinois River, and he reported tak- ing it upstream as far as Peoria Lake in 1912. In that same year Forbes & Rich- ardson (1913:525, 533, & 536) took this species at Ottawa (Starved Rock pool) near the mouth of the Fox River and in the Hennepin-Chillicothe section. By the mid-1920's pollution had eliminated the fragile heel-splitter north of the Nar- rows at Peoria (Richardson 1928:456- 457). In the 1966 survey this mussel ranked 12th in abundance (Tables 6 and 7) ; 42 live fragile heel-splitters were taken between river miles 1.0 and 196.1 (Table A- 3). These shells ranged from 2 to 13 years in age. The 2-year- old mussels (two specimens) were col- lected in the Alton pool, and the heights of these specimens, were 0.8 inch. The shell of this species was of no commer- cial value. Since the fragile heel-splitter was tak- en in the Peoria-Pekin section, it ap- parently was one of the mussels more tolerant to pollution; however, it was not collected in the upper part of the Peoria pool. By 1966 the fragile heel- splitter had re-extended its upstream range from the Peoria Narrows (mid- 1920's) to Henry (river mile 196.1), a distance of about 29.5 miles. Apparently this species was about as abundant in 1966 as it was before 1913. The fish hosts known for this mussel are the freshwater drum and the white Feb., 1971 Starrett: Mussels of the Illinois River 331 crappie (Baker 1928:248). These fishes still occur in the Illinois River. Museum Records.—Thompson Lake FMNH 23218; Quiver Lake (1955 Parmalee) ISM 1034-1035; Havana (1910 Baker) UIMNH 22159; 1 mile W of Havana, backwater slough of the Illinois River (1953 Parmalee) ISM 264-267; Meredosia (1930 Morrison) USNM 678655 and (1955 Parmalee) ISM 1380-1381; Naples (1955 Parma- lee) ISM 1109-1111; 1 mile N of Hardin (1956 Parmalee) ISM 2200- 2201 (dead) ; and 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678579. Live Mussel Records ( 1966 Survey). — River mile 1.0 (LB), 13.0 (RB), 42.2- 42.3 (LB), 47.5 (LB), 66.0-66.4 (LB), 75.8 (RB), 87.3 (RB), 110.1 (LB), 129.8-130.4 (RB), 145.7 (RB), 154.4- 154.5 (RB), 161.2 (LB), 165.3-166.1 (RB), 166.3 (LB), 174.1 (LB), 174.9 (LB), and 196.1 (LB). OSM 17695, 17715, 17727, and 17740; FMNH 156951 (2), 156960 (2), 156974 (2), 156993 (4), and 156994 (2). Old Shell Records (1966 Survey).— River mile 15.0, 66.0-66.4, 75.8, 83.0, 86.6-86.8, 145.7, 156.0, and 196.3- 198.1. OSM 18213, 18224, 18267, 18272, 18335, 18372, and 18447. Liliput Shell Carunculina parva (Barnes, 1823) (Plate 4-23) Carunculina parva (Barnes) : Parmalee (1967:59) Richardson (1928:457) MCZ Unio parvus Bar.: Strode (1891a: 133) Lampsilis parvus Bar.: Kelly (1899:401) Lampsilis parva Barnes: Baker (1906:67-68) Forbes & Richardson (1913:533) Lampsilis parva (Barnes) : Danglade (1914:10) Toxolasma parvum parvum (Barnes) : FMNH Toxolasma parva Barnes: Morrison (pers. comm., 4 January 1968) Danglade (1914:45) regarded the liliput shell as a rare species in the Illi- nois River, and in his survey observed a single specimen taken from Peoria Lake. However, concerning the abun- dance of this species, Parmalee ( 1967 : 59) stated: "It has also been observed inhabit- ing the shallow, mud banks and backwater sloughs of the Illinois River in considerable numbers." Kelly's (1899:401) data indicated that this shell occurred abundantly in the river in the Havana area in the 1896- 1897 period. In 1890 Strode (1891a: 133) collected the liliput shell in Thomp- son Lake (now drained and leveed off) near Havana. Forbes & Richardson (1913:533 & 536) took this species in 1912 at Hennepin and in the Henry- Chillicothe section. Dr. William Clench (pers. comm., 12 August 1969) advised the author that a specimen of this spe- cies taken from the river at Peru (pre- 1910) was in the MCZ collections. By the mid-1920's pollution had restricted the upstream distribution of this species to no farther than Middle Peoria Lake (Richardson 1928:456-^57). In the early 1930's Morrison (pers. comm., 4 January 1968) collected this shell at Meredosia. However, in the 1950's Parmalee (pers. comm., 21 No- vember 1966) did not collect a live lili- put shell at Meredosia or at any of his other collecting sites in the river proper athough he did take live specimens of this mussel in 1953 from a backwater slough about 1 mile west of the river and Havana. In the 1966 survey a sin- gle live specimen of this species was taken by wading at river mile 1.0. Ap- parently by 1966 the liliput shell was confined to the extreme lower section of the river proper. The host fish for this mussel is not known. Museum Records.—Peru (pre-1910) MCZ; Peoria (1931 Morrison) USNM 678659 (dead); Quiver Lake (1955 Parmalee) ISM 1053 (dead) ; 1 mile W of Havana in backwater slough (1953 Parmalee) ISM 268; Beardstown (1870) FMNH 14337; Meredosia (Hinkley) UIMNH 4307, (1909 Baker) UIMNH 21361, (1930 Morrison) USNM 678656 -678657, and (1932 Morrison) USNM 332 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 678658; 1 mile N of Hardin (1956 Parmalee) ISM 2207 (dead) ; and IIU- nois River without locality (1870's) BK. Live Mussel Records ( 1966 Survey) . — River mile 1.0 (LB). OSM 18016. Old Shell Records (1966 Survey).— River mile 83.0 and Quiver Lake. OSM 18266 and 18308. Black Sand-Shell Ligumia recta (Lamarck, 1819) Ligumia recta (Lamarck) : Parmalee (1967:74; 1962:9) Unio rectus Lam. : Calkins (1874:44) Lampsilis rectus Lam.: Kelly (1899:401) Lampsilis recta Lamarck: Baker (1906:66) Lampsilis recta (Lam.) : Danglade (1914:10) Ligumia recta latissima Rafinesque, 1820: Morrison (pers. comm., 4 January 1968) Ligumia latissima Raf. : MCZ In the early 1870's Calkins (1874:44) found the black sand-shell occurring abundantly in the upper Illinois River (Starved Rock pool), and he remarked that the shells here attained a length of 6-7 inches. In the 1896-1897 period Kelly (1899:401) examined 10 specimens of this species collected in the vicinity of Havana. Danglade (1914:37 & 45) considered this shell rather common in 1912; however, he did not take it north of Chillicothe. Forbes & Richardson (1913) and Richardson (1928) did not record this species from the upper and middle river between 1912 and 1925. The black sand-shell was not taken alive from the Illinois River in the 1966 survey. Neither Morrison (pers. comm., 4 January 1968) in the early 1930's nor Parmalee (pers. comm., 21 November 1966) in the 1950's collected a live speci- men of this species from the river. The museum and old shell records indicated that the black sand-shell for- merly was distributed throughout most of the Illinois River. Apparently by 1912 pollution had eliminated this shell above Chillicothe and by 1930 from the entire river. The host fish for this mussel is not known. Museum Records.—La Salle County (Baker) UIMNH 15134; Peoria (1870's) BK; Havana (1912) INHS a-78; Mere- dosia (1907 Freeland) USNM 676953 and (pre-1910) MCZ; 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678580; Calhoun County (1928 Baker) UIMNH 27296; Illinois River stat. K-j (1907 Freeland & Williams) USNM 676964; and Illinois River without lo- cality (1870's) BK. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— River mile 75.8, 129.8, 145.7, 156.0, 240.4, and 253.5-256.5. OSM 18259, 18320, 18336, 18373, 18469, and 18483. Pond Mussel Ligumia subrostrata (Say, 1831) Ligumia subrostrata (Say) : Parmalee (1967:75) Lampsilis subrostrata Say (= mississip- piensis Conrad) : Baker (1906:67) Baker (1906:67) reported that Derr collected this shell at Peru in La Salle County ; however, the name of the stream was not mentioned. Morrison (pers. comm., 27 November 1967) was of the opinion that this specimen undoubtedly was taken in a tributary stream rather than in the Illinois River. In 1954 Parmalee (pers. comm., 21 November 1966) collected a pond mussel in a mud slough backwater 1 mile west of Havana and the Illinois River. The author was of the opinion that these records of subrostrata should be con- sidered as records from the Illinois River valley rather than from the Illinois River and its adjoining bottomland lakes. Museum Records.—None. Live Mussel Records ( 1966 Sur\-ey') . — None. Old Shell Records (1966 Sur%ey).— None. Feb., 1971 Starrett: Mussels of the Illinois River 333 Rainbow-Shell Villosa iris iris (Lea, 1829) Villosa (= Micromya) iris (Lea) : Parmalee (1967:75-76) Unio iris Lea: Calkins (1874:42) Calkins (1874:42) reported that this species was not abundant in the Illinois River at La Salle County (Starved Rock pool) in the early 1870's. No museum specimen of the rainbow-shell was located from the Illinois River. Morrison (pers. comm., 14 June 1968) informed the au- thor that the collections of the U.S. National Museum contained a specimen (USNM 58260) of this species taken by Calkins from the Vermilion River (a tributary stream of the Illinois) in La Salle County. It was apparent from this record that Calkins was quite familiar with the rainbow-shell, and no doubt he identified it properly as U. iris in his Illinois River collections. According to Parmalee ( 1967 : 76) , this species still occurs in the Kankakee, Fox, and Vermilion rivers, tributary streams of the upper Illinois River. The Fox and Vermilion rivers empty into the Illinois near the vicinity where Calkins made his collections. Relative to the ecology of this species, Ligumia iris novieboraci (Lea), Baker (1928:262) stated that it is: "A mussel of small streams, living below riffles on a sandy or mud bot- tom. Also in riffles on a gravel bottom in less than a meter of water." In the Starved Rock area where Cal- kins (1874:11) collected, the river was shallow and the bottom sandy. Evidently this habitat was suitable for the support of a small population of rainbow-shells when Calkins (1874:42) made his col- lections, and his record of its occurrence there, in the author's opinion, was au- thentic. Later this excellent mussel habi- tat was destroyed by pollution, siltation, and the Starved Rock dam. The fish host for this mussel is not known. Museum Records.—None. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. Yellow Sand-Shell Lampsilis anodontoides forma anodontoides (Lea, 1831) Lampsilis anodontoides (Lea) : Parmalee (1967:64) Forbes & Richardson (1913:536) Danglade (1914:10) Richardson (1928:457) Unio anodontoides Lea: Calkins (1874:41) Strode (1891a: 133) Lampsilis anodontoides Lea: Kelly (1899:401) Lampsilis anodontoides Lea (= teres Say) : Baker (1906:66) Lampsilis (Ligumia) teres teres (Raf.) : FMNH Lampsilis teres Rafinesque, 1820: Morrison (pers. comm., 4 January 1968; 4 June 1968) Before 1899 L. anodontoides f. anodon- toides was not separated from L. anodon- toides f. fallaciosa (Smith 1899) ; conse- quently, the early published records of the occurrence of the yellow sand-shell in the Illinois River by Calkins (1874: 41), Strode (1891a:133), and Kelly (1899:401) may have referred to either or both forms of anodontoides. In the case of Calkins' record of anodontoides, Morrison (pers. comm., 4 June 1968) wrote : "In W. W. Calkins, Proc. Ottawa Acad. Sci., 1874, list of La Salle County, there is the listing of Unio anodontoides from the Illinois River. We have 5 specimens from W. W. Calkins (from the Stearns Collec- tion) from the Illinois River, prob- ably representing this record. These shells, catalogued February 2, 1886, as USNM 40773, were labeled ano- dontoides. Actually, only the three largest shells of this lot are teres (anodontoides) as we know it today. The two smaller ones are fallaciosa, 334 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 so Calkins' record from La Salle County also included fallaciosa from this stretch of the Illinois River. F. C. Baker's record of 'L. anodon- toides' (Moll. Chicago Area, I, p. 100, 1898) corroborates the occur- rence of fallaciosa farther upstream in the Illinois system and/or north- ward than teres. Baker's description, p. 100, of the beak sculpture and the figures of his shells, especially the smaller, lower figures, prove that he recorded only Lampsilis fallaciosa (which was named only a few months later) from the Des Plaines River and its tributaries only. In the 1906 Catalogue of IlHnois Shells, Baker put this Cook County record under fallaciosa (p. 66) and listed teres only as La Salle County (Huett) and 'Northern Illinois' (Calkins). Since Baker did not have access to our USNM 40773 specimens, he did not know that Calkins had both teres and fallacio- sa in the La Salle County, Illinois River collections, collected alive ear- lier and published in 1874. The fallaciosa of Calkins are now re- catalogued as USNM 679106." Concerning the yellow sand-shell in the Illinois River in 1912, Danglade (1914: 45) stated: "This species is found sparingly throughout the upper river, but is fairly abundant in the Hardin dis- trict, where it is in sufficient quantity to be sorted out and sold separately at an advanced price. This shell is the most valuable of the fresh- water mussels .... It prefers deep water and clean sandy bottoms." Danglade (1914:37) did not collect this shell above Peoria Lake ; however, Forbes & Richardson (1913:536) took it in 1912 in the Henry-Chillicothe section of the river. In the mid-1920's Richardson (1928:456-457) failed to collect the yellow sand-shell in his survey of Peoria Lake. In 1930 Morrison (pers. comm., 4 January 1968) took this mussel alive at Meredosia. Parmalee (pers. comm., 21 November 1966) did not take it at Mere- dosia in 1955 but did collect a live speci- men downstream at Naples. No live yellow sand-shell was taken in the 1966 survey. Of the mussel species tested by Ellis (1936:39), the yellow sand-shell (L. teres) was the most readily killed by silt deposits. Evidently siltation and pollution adversely afTected this mus- sel in the Illinois River. The fish host for the yellow sand-shell is the longnose gar, Lepisosteus osseus (Linnaeus), and other possible fish hosts are the shortnose gar, Lepisosteus pla- tostomus Rafinesque; alligator gar, Lepi- sosteus spatula Lacepede; green sunfish; orangespotted sunfish, Lepomis humilis (Girard) ; largemouth bass; white crap- pie; and black crappie (Baker 1928:267) . All of these fishes, except the alligator gar, still occur in the Illinois River. Museum Records.—La Salle County (1870's Calkins) USNM 40773; Havana (1895 Hay) FMNH 6392 and (pre-1900 Strode) FMNH 9123; Frederick (Wet- tengel) FMNH 68411; Meredosia (1912 Danglade) USNM 678616 and (1930 Morrison) USNM 678660; Naples (1955 Parmalee) ISM 928 (dead) and 1158; Buckhom Landing (1912 Danglade) USNM 678617; and 10 miles below Har- din (1907 Bartsch stat. 110) USNM 678581. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— River mile 167.2. OSM 18379. Slough Sand-Shell Lampsilis anodontoides forma fallaciosa (Smith, 1899) (Plate 3-16) Lampsilis fallaciosa Rafinesque [sic] : Parmalee (1967:65; 1962:9) Unio anodontoides Lea: Calkins (1874:41) Lampsilis fallaciosa (Smith) Simpson: Baker (1906:66) Forbes & Richardson (1913:533) Richardson (1928:457) Lampsilis fallaciosa (Smith) : Danglade (1914:10) Lampsilis fallaciosa Smith, 1898: Morrison (pers. comm., 4 January 1968; 4 June 1968) Feb., 1971 Starrett: Mussels of the Illinois River 335 Lampsilis anodontoides Lea: MCZ Lampsilis (Ligumia) teres fallaciosa (Simpson) : FMNH Danglade (1914:37 & 45) reported that the slough sand-shell occurred abun- dantly in the Illinois River in 1912 and that he collected it at all of his principal stations between Henry and Grafton. Concerning the ecology of this mussel in the river, Danglade (1914:45) stated that it is: "usually found standing on end bur- rowed in the mud of sloughs and bays or along the shore where there is but little current." These habits of the slough sand-shell made it difficult for us to catch it with the crowfoot bar and dredge in the 1966 survey. In the survey 53 live specimens of this shell were collected (Table A-3) of which 66.0 percent were taken by wading. This shell ranked ninth in abundance; however, it probably occurred more abundantly than was reflected by our collections (Tables 6 and 7 ) . The author believed that if more wading collections had been made in the survey this mussel probably would have ranked about sixth in abundance rather than ninth. The mean height of the slough sand-shell was 1.5 inches (range 1.0-2.0 inches), and the ages of the shells ranged from 3 to 12 years. The shell of this species was of no commercial value. The Lampsilis anodontoides shells from the Illinois River in the Museum of Comparative Zoology were checked for the author by Dr. Stansbery (pers. comm., 20 January 1970) and he determined them to be form fallaciosa. Calkins (1874:41) collected this shell in the early 1870's as discussed above under L. anodontoides f. anodontoides, in the river at La Salle County (Starved Rock pool). In the 1966 survey two live slough sand-shells were taken at about river mile 226.1 (at La Salle) , only about 5 miles below Starved Rock where Cal- kins ( 1874 : 11 ) did much of his collecting in the river. The slough sand-shell was collected about 18.5 miles farther up- stream in 1966 than it was in 1912 by Forbes & Richardson (1913:533). In the mid-1920's Richardson (1928:457) did not take this shell above the lower end of Upper Peoria Lake. Apparently the slough sand-shell was one of the more tolerant species of mussels to pollution in the Illinois. The white crappie, shortnose gar, and the shovelnose sturgeon, Scaphirhynchus platorynchus (Rafinesque) , are believed to be the host fishes for the slough sand- shell ( Baker 1 928 : 269 ) . The shovelnose sturgeon is now extremely rare in the Illinois River. Museum Records.—La Salle County (1870's Calkins) USNM 679106; Peru (pre-1910) MCZ 70918; Spring Valley, "Sandy River Drift" (1924 Morrison) USNM 678668 (dead) ; Mossville (1925) INHS C-5; Peoria Narrows (1924) INHS 1-B; Peoria, above bridge (1912 Danglade) USNM 678618; Pe- oria (1870's) BK, (1931 Morrison) USNM 678661 and 678663, and (pre- 1910) MCZ 29925; between Pekin and Havana USNM 677042; Liverpool (1957 Parmalee) ISM 2370-2377; Quiver Lake (1955 Parmalee) ISM 996-1001; Havana (1894 Baker) UIMNH 22151, (1909 Freeland) USNM 678619, (1912 Danglade) USNM 678620, and (1912) INHS a- 22-S; Frederick (pre-1917 Zetek) FMNH 67968; 2 miles N of Beards- town (1959 Parmalee) ISM 2869-2870; Beardstown (1910) INHS F-92; Mere- dosia (1930 Morrison) USNM 678662, (1932 Morrison) USNM 678664, and (1955 Parmalee) ISM 1415-1418; Na- ples (1955 Parmalee) ISM 1159-1164; 1 mile N of Hardin ( 1956 Parmalee) ISM 2204-2205 (dead) ; 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678582 and (1907 Bartsch stat. 109) USNM 678583; 10 miles below Hardin (1907 Bartsch stat. 110) USNM 678584; and Illinois River without locality (1907 Freeland & Williams) FMNH 11231. Live Mussel Records ( 1966 Survey). — River mile 1.0 (LB), 13.0 (RB),'47.5 (LB), 56.3 (LB), 57.6 (RB), 58.9 (RB), 66.0-66.4 (LB), 73.7 (RB), 75.8 (RB), 86.8 (LB), 87.3 (RB), 87.9 (LB), 95.8 (LB), 100.0-100.5 (LB), 129.8-130.4 336 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 (RB), 163.0 (LB), 164.5-165.3 (LB), 166.3 (LB), 167.7 (LB), 169.5 (LB), 174.1-174.9 (RB), 174.1 (LB), 174.9 (LB), 184.5 (RB), 196.1 (LB), 198.1 (RB), 224.0 (LB), and 225.8-226.1 (RB). OSM 17347 (3), 17696, 17718, 17721, 17734, 17741, 17745, and 17748; FMNH 156980 (2), 157001 (2), and 157007 (10). Old Shell Records (1966 Survey).— River mile 15.0, 44.9, 66.0-66.4, 75.8, 83.0, 86.6-86.8, 106.8, Quiver Lake, 129.8, 145.7, 156.0, 184.5, 196.1, and 196.3-198.1. OSM 18206, 18214, 18260, 18268, 18273, 18297, 18309, 18337, 18374, 18386, and 18435. Fat Mucket Lampsilis radiata luteola (Lamarck, 1819) (Plate 3-17) Lampsilis siliquoidea (Barnes) : Parmalee (1967:68; 1962:9) Richardson (1928:457) MCZ Unio luteolus Lam. : Calkins (1874:42-43) Lampsilis luteolus Lam. : Kelly (1899:401) Lampsilis luteola Lamarck {=siliquoides Barnes, distans Anthony) : Baker (1906:65) Lampsilis luteola (Lam.) : Danglade (1914:10) Forbes & Richardson (1913:533) Lampsilis luteola Lamarck, 1819: Morrison (pers. comm., 4 January 1968) Lampsilis (Ligumia) siliquoidea siliquoi- dea (Barnes) : FMNH In the early 1870's Calkins (1874:42- 43) found the fat mucket occurring abundantly in the Illinois River at La Salle County (Starved Rock pool). Kel- ly (1899:401) examined 11 specimens collected in the Havana area in the 1896- 1897 period. Danglade (1914:46) con- sidered the fat mucket widely distributed in the Illinois and found that it was more plentiful in Peoria Lake than elsewhere. In 1912 Danglade (1914:37) took this mucket at all of his principal stations between Henry and Beardstown but col- lected it only intermittently at his sta- tions between Beardstown and Grafton. In the 1966 survey of the Illinois River only eight live fat muckets were col- lected (Table A-3). Stansbery (pers. comm., 26 September 1967) referred to these specimens as Lampsilis radiata siliquoidea (Barnes, 1823) based on the intergrading of radiata and siliquoidea discovered by Clarke and Berg (1959: 58-62). Later, Stansbery (pers. comm., 14 August 1969) advised the author to refer to the Illinois River material as Lampsilis radiata luteola (Lam., 1819). The fat mucket ranked 16th in abun- dance in the 1966 survey (Tables 6 and 7) and the ages of the specimens col- lected ranged from 11 to 20 years. Live fat muckets were collected in 1966 between river miles 110.5 (below Havana) and 169.3 (Peoria Lake). Six of the eight fat muckets came from Pe- oria Lake, where in 1912 Danglade (1914:46) also found this mussel oc- curring in its greatest abundance. In 1912 Forbes & Richardson (1913:533) collected the fat mucket upstream as far as Hennepin. In the mid-1920's Rich- ardson (1928:456-457) found that pol- lution had limited the upstream distri- bution of this mussel to the lower end of Upper Peoria Lake, only about 3 miles above its farthest upstream location in the 1966 survey. In the Alton pool, Mor- rison (pers. comm., 4 January 1968) collected this mussel at Meredosia in 1930, and in 1955 Parmalee (pers. comm., 21 November 1966) collected it at Meredosia and Naples. As indicated above, the fat mucket was not taken alive in the Alton pool in the 1966 sur- vey; however, a single specimen of this mussel was observed in a culled commer- cial shell pile at Meredosia. The present scarcity and limited range of this once abundant mussel together with the lack of any young breeding stock portended its possible elimination from the Illinois River. The bluegill, yellow perch, and wall- eye, Stizostedion vitreum vitreum (Mitchill), are the known natural host Feb., 1971 Starrett: Mussels of the Illinois River 337 fishes for the fat mucket (Baker 1928: 273), but the walleye is uncommon in the Illinois River. Museum Records. — La Salle (pre- 1910) MCZ; Peru (pre-1910) MCZ; Havana (1894 Baker) UIMNH 22145, (1895 Hay) FMNH 14074, (1910 Zetek) FMNH 59306 and 68163, and (1912 Danglade) USNM 678621 ; Mere- dosia (1930 Morrison) USNM 678665, (pre-1910) MCZ, and (1955 Parmalee) ISM 1413-1414; Naples (1955 Parma- lee) ISM 1165-1169; and 1 mile below Hardin (1907 Bartsch stat. 109) USNM 678585. Live Mussel Records ( 1966 Survey). — River mile 110.5 (RB), 122.2 Quiver Lake (LB), 166.6 (LB), 167.7 (LB), 168.2 (RB), and 169.3 (RB). OSM 17725, 17730 (2), 17733, and 17739; FMNH 156997. (1969): River mile 162.3 (LB). OSM 22277. Old Shell Records (1966 Sur\ey).— River mile 66.0-66.4, 75.8, 106.8, Quiver Lake, 145.7, 156.0, 167.2, 184.5, and 196.3-198.1. OSM 18158, 18226, 18261, 18298, 18338, 18375, 18380, and 18448. Pocketbook Lampsilis ventricosa (Barnes, 1823) Lampsilis ventricosa (Barnes) : Parmalee (1967:70; 1962:9) Forbes & Richardson (1913:525 & 533) Richardson (1928:457) Danglade (1914:10) MCZ Lampsilis ventricosus Bar.: Kelly (1899:401) Lampsilis ventricosa Barnes (= occidens Lea, subovata Lea) : Baker (1906:64) Lampsilis (Lampsilis) cardium (Raf.) : FMNH Lampsilis occidens: Richardson (1928:457) Lampsilis cardium Rafinesque, 1820: Morrison (pers. comm., 4 January 1968) No live pocketbook was taken in the 1966 survey of the Illinois River. Neither Morrison (pers. comm., 4 January 1968) in the early 1930's nor Parmalee (pers. comm., 21 November 1966) in the 1950's collected a live pocketbook from the Illi- nois. Cvancara (1963:223) recognized the possibility that a cline may exist in the Lampsilis ovata complex; however, he mentioned that considerable study re- mained to be done on the anatomy and genetics of the three species involved in this complex. Morrison (pers. comm., 4 January 1968) referred to the Illinois River specimens of this mussel in the U. S. National Museum collections as L. cardium Rafinesque, 1820, and Stans- bery (pers. comm., 13 January 1968) identified the two old shells collected in the 1966 survey as L. ovata forma ventri- cosa (Barnes, 1823). Since no special study was made of the limited number of Illinois River museum specimens available, the author decided to refer to them here merely as L. ventricosa, the usual reference to the northern form (Cvancara 1963:222). This species was not taken in the upper river by Calkins (1874). In 1912 a live pocketbook was collected by Forbes & Richardson (1913:525) in the Illinois River at Ottawa near the mouth of the Fox River. In that same year they (1913:533) took two dead shells of this species at Hennepin. Danglade (1914:37) did not collect this species in the Henry-Chillicothe section of the river, but he did take it at most of his principal stations between Peoria Lake and Grafton. In the 1896-1897 period Kelly (1899:401) examined 10 speci- mens of this mussel from the Havana area. In 1912 Danglade (1914:46) con- sidered the pocketbook an uncommon mussel in the Illinois. By the mid-1920's this species had disappeared from Peoria Lake (Richardson 1928:457). Accord- ing to Parmalee (1967:70): "The Pocketbook thrives on a sand or gravel bottom, in current at depths of less than one foot to over 10 feet." Siltation and pollution probably eliminated this mus- sel from the Illinois River between 1918 and 1930. The natural host fishes for the pocket- 338 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 book are the white crappie and the sauger (Baker 1928:284). Museum Records.—Peru (pre- 1910) MCZ; between Pekin and Havana (1907 Freeland & Williams) USNM 677059; Havana (1894 Baker) UIMNH 22154; Meredosia (1907) USNM 676952; Flor- ence (1909 Freeland) USNM 678622; 1 mile below Hardin ( 1907 Bartsch stat. 108) USNM 678586; 10 miles below Hardin (1907 Bartsch stat. 110) USNM 678587; and Illinois River without lo- cality (1895 Hay) FMNH 14070, (pre- 1943 Webb Coll.) FMNH 23307, and (1870's) BK. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— River mile 145.7 and 219.4. OSM 18339 and 18466. Lampsilis orbiculata Complex Whether Lampsilis orbiculata and L. higginsi(i) are separate species remains an open question (Stansbery, pars. comm.. 26 September 1967; van der Schalie, pers. comm., 19 January 1968) . Morrison (pers. comm., 27 November 1967) recognizes L. ahruptus Say, 1831 {"orbiculatus auct, NON Hild.") and L. higginsi Lea, 1868 as t\\'o separate species. Stansbery (pers. comm., 26 Sep- tember 1967) considers that: "Lampsilis orbiculata and Lamp- silis higginsii are distinguishable but I have not enough specimens (nor have I seen enough material in other museums) to enable me to in- fer whether or not they are con- specific. This being the case, I car- ry them simply as forms of the same nominal species. I will not be sur- prised if they are found to be con- specific nor would I be surprised to find they are different species. I just don't know at present." Since this is an unsettled problem need- ing further study, the author has fol- lowed Stansbery's and van der Schaile's opinions and has treated the Illinois River material as forms of Lampsilis orbiculata. No live specimen belonging to this complex was taken in the 1966 survey of the river. As a result, the author has depended upon old shells taken in the 1966 survey, literature records, and museum records to establish the former occurrence of this complex in the Illi- nois River. Since the identification of the two forms, or species, involved here is quite difficult, the question is raised as to the validity of the Illinois River records of the two species or forms of this complex in the literature and of the identifications made years ago of mu- seum specimens. The museum speci- mens of this complex from the Illinois River that have not been checked re- cently are listed as L. orbiculata com- plex. This list also includes the speci- mens examined by the author and one old shell taken in the 1966 survey and checked by Dr. Stansbery. Other Illi- nois River specimens belonging to this complex and deposited in various col- lections were checked by the following persons: Benjamin Koons' specimens, Illinois Natural History Survey speci- mens, and U. S. National Museum col- lections by Dr. Morrison; subfossil shells taken in the 1966 survey by Dr. Stans- bery; and the Illinois State Museum collection by Dr. PaiTiialee. The author has used the identifications made by these taxonomists as the basis for his dis- cussion of the two forms or species of this complex under the next headings of L. orbiculata forma orbiculata and L. orbiculata forma higginsii. Museum Records. — (L. orbiculata complex) Starved Rock (Hinkley) UIMNH 4117: La Salle County (Dan- iels) UMMZ 86345; Havana (1894 Baker) UIMNH 22153 and (Smith) UMMZ 84351; and Illinois River with- out locality (1861 Hall) FMNH 14233. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— River mile 253.5. OSM 18484. Lampsilis orbiculata forma orbiculata (Hildreth, 1820) Lampsilis orbiculata (Hildreth) : Parmalee (1967:67) Danglade (1914:10) Lampsilis orbiculata Hildreth: Baker (1906:66) Lampsilis abruptus Say, 1831: Morrison (pers. comm., 4 January] 1968) According to Baker (1906:66) this form or suecies was collected from the Feb., 1971 Starrett: Mussels of the Illinois River 339 Illinois River by Strode. Concerning orbiculata, Danglade (1914:46) stated: "There are two examples in our collection, one from Chillicothe and the other from Peoria. The nacre of one is rather pinkish. This spe- cies is difficult to separate from higginsii, but is generally more southern in distribution." Morrison (pers. comm., 4 January 1968) examined two specimens in the collections of the U. S. National Mu- seum taken from the Illinois River 1 mile below Hardin in 1907. He identi- fied them as L. abruptus and L. hig- girtsi. This was of particular interest in that both of these species or forms had been found occurring together in the river. Morrison (pers. comm., 27 No- vember 1967) commented that: "The geographic range of abruptus overlaps that of higginsi in the region of the Ohio- Mississippi confluence." The only record recognized by the author of the occurrence of L. orbiculata f. orbiculata {abruptus) in the Illinois was the one mentioned above from the lower river furnished by Dr. Morrison. It appeared to the author that this form or species was never common in the Illinois and occurred only in the lower part of the river. The literature citations given above for the occurrence of L. orbiculata f. orbiculata may refer to either or both of the forms or species of the L. orbiculata complex. This mus- sel had probably disappeared from the Illinois River before 1930. The fish host of L. orbiculata i. or- biculata is not known. Museum Records.— 1 mile below Har- din (1907 Bartsch stat. 108) USNM 678666. Live Mussel Records ( 1966 Surrey ) . — None. Old Shell Records (1966 Survey).— None. Higgin's Eye Lampsilis orbiculata forma higginsii (Lea, 1857) Lampsilis higginsii (Lea) : Parmalee (1967:67) Danglade (1914:10) Baker (1928:294) Unio orbiculatus Hildreth: ralli'ns (1874-44'; Lampsilis higginsii Lea: Kelly (1899:401) Baker (1906:66) Lampsilis higginsii var. grandis Simpson, 1914: Simpson (1914:79) Lampsilis higginsi Lea, 1868: Morrison (pers. comm., 4 January 1968) Calkins (1874:44) found U. orbicu- latus occurring abundantly in the Illi- nois River at La Salle County (Starved Rock pool) in the early 1870's. Mor- rison (pers. comm., 4 January 1968) identified a specimen collected by Cal- kins from the river as L. higginsi. This record and Simpson's (1914:79) re- port of finding L. higginsii var. grandis occurring fairly abundantly in the river near Utica—in the vicinity where Cal- kins (1874:11) collected U. orbiculatus —led the author to believe that Calkins took L. orbiculata f. higginsii rather than L. orbiculata f. orbiculata from the river in La Salle County. The author submitted four specimens of the L. orbiculata complex from the Benjamin Koons collection and the col- lection of the Illinois Natural History Survey to Dr. Morrison for identifica- tion. Morrison (pers. comm., 4 January 1968) stated that: "The four specimens sent for check are indeed Lampsilis higginsi Lea. The large female with the more widely produced post basal region is the form called Lampsilis higginsi grandis by Simpson (1914:79). Without a great many more speci- mens available for study, I would not use the grandis form name." Two of these specimens were collected from the river at Havana in 1895 and 1912. Kelly (1899:401) reported that he e.xamined a single specimen of L. higginsii in the 1896-1897 period from the Havana area of the river. A subfossil shell collected in the 1966 survey at river mile 94.3 (below Brown- ing) was identified by Stansbery (pers. comm., 13 January 1968) as Lampsilis orbiculata f. higginsii. Parmalee (pers. comm., 29 June 1967) indicated that the Illinois State Museum contained two specimens of L. higginsii collected in the 1870's at Peoria. Dancrladp M914:371 rcDorted takine 340 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 higginsii at Chillicothe, Peoria Lake, Ha- vana, Bath, Beardstown, Meredosia, Florence, Pearl, Kampsville, Hardin, and Twelve-Mile Island. He (1914:46) con- sidered higginsii as uncommon but wide- ly distributed, especially in the lower half of the river. Neither Forbes & Richardson (1913) in 1912 nor Rich- ardson (1928) in the mid-1920's re- ported taking a mussel belonging to the L. urbiculata complex above Peoria. Ap- parently higginsii formerly was widely distributed in the Illinois River before 1900 and gradually was eliminated by pollution and siltation before 1930. The known host fish for higginsii is the sauger (Baker 1928:294). As men- tioned earlier, this is an uncommon fish in the Illinois River. Museum Records. — Peoria (1870's) ISM 769-770; Havana (1895) INHS and (1912) OSM 23250; 1 mile below Hardin (1907 Bartsch stat. 108) USNM 678588; and Illinois River without local- ity (Calkins) USNM 58129 and (1870's) OSM 23249. Live Mussel Records ( 1966 Survey). — None. Old Shell Records (1966 Survey).— River mile 94.3. OSM 18287. Snuffbox Dysnomia triquetra (Rafinesque, 1820) Dysnomia triquetra (Rafinesque) : Parmalee (1967:62) Uriio triangularis Barnes: Calkins (1874:45) Truncilla triquetra Rafinesque (= tri- angularis Lea) : Baker (1906:63) The snuffbox was taken by Calkins (1874:45) in the Illinois River in La Salle County (Starved Rock pool) in the early 1870's. According to Baker (1906: 63), this species was collected from the river by Handwerk. The author exam- ined a shell (UIMNH 15257) of this species collected by Baker at La Salle; however, the name of the stream was not recorded. Possibly this shell came from the Illinois. Another shell of this species, examined by the author, was collected by Baker in 1911 from the Illinois River in Fulton County. The snuffbox was not taken from the river by Danglade (1914). Evidently this spe- cies was never common in the Illinois and was probably quite scarce by 1911. The fish host of the snuffbox is not known. Museum Records. — Fulton County (1911 Baker) UIMNH 3766. Live Mussel Records ( 1966 Survey) . — None. Old Shell Records (1966 Survey).— None. EFFECTS OF POLLUTION In the preceding section it has been established that at least 49 different kinds of mussels were present in the Illinois River and its adjoining bottomland lakes in the 1870-1900 period (Table 5). Ap- parently between the 1870-1900 and Table 9.—Kinds of mussels extirpated from the Illinois River and its bottomland lakes be- tween 1900 and 1969.'' Cumberlandia monodonta (Spectacle-Case) Fusconaia flava i.flava (Wabash Pig-Toe) Quadrula metanevra (Monkey-Face) Cyclonaias tuberculata (Purple Warty-Back) Plethobasus cyphyus (Bullhead) Pleurobema coccineum f. solida Pleurobema pyramidatum Elliplio crassidens (Elephant's Ear) Elliptio dilatatus (Lady-Finger) Uniomerus tetralasmus (Pond-Horn)'' Lasmigona coslata (Fluted Shell) Alasmidonta calceolus (Slipper-Shell) Alasmidonta marginata (Elk-Toe) Strophitus undulalus (Squaw Foot) Anodontoidesjerussacianus (Cylindrical Paper Shell) Actinonaias ligamentina (Mucket) Plagiola lineolala (Butterfly) Proptera capax (Fat Pocketbook) Ligumia recta (Black Sand-Shell) Villosa iris iris (Rainbow-Shell) Lampsilis anodontoides f. anodontoides (Yellow Sand-Shell) Lampsilis ventricosa (Pocketbook) Lampsilis orbiculata f. orbiculata Lampsilis orbiculata f. higginsii (Higgin's Eye) Dysnomia triquetra (SnuflTbox) H « Anodonta suborbiculata (Heel-Splitter) was not collected from the mainstream of the Illinois River in 1966, but one living specimen was taken in a bottomland lake adjoining the river. ^ Not reported from the mainstream of the Dli- nois River. 1906-1912 periods^ three typical small stream species of mussels (.4. calceolus, A. marginata, and V. iris iris) were ex- ^ •The 1870-1900 and 1906-1912 periods were chosen arbitrarily and were not necessarily inclusive dates of th2 occurrence of a mussel species in the Illinois River. However, at some time during a period in which a species was listed as present, it was known to have occurred in the river. Feb., 1971 Starrett: Mussels of the Illinois River 341 tirpated from the mainstream of the Illi- In the 1966-1969 period only 24 kinds "ois. of mussels were taken alive, indicating MILES FROM MISSISSIPPI RIVER Fig- 9.—Kinds of living mussels taken in the Illinois River in 1912 and in the 1966-1969 period. Note that by 1912 pollution already had affected the mussel fauna of the upper part of the river and that by 1966 the mussel fauna of virtually the entire river had been affected. In the lower part of the river the mussel fauna changed less than it did in the remainder of the river betw/een 1912 and 1966. In 1966 the commercial mussel fishery was confined to the lower 87 miles of the river, but in 1969 it was resumed in the vicinity of Peoria. LUKE ^ UCHDV aVT' I L. DISTRIBUTION OF MUSSELS IN THE H I 1 BEFORE I90C CD 1912 Fig. 10.—Changes in the distribution of the more common mussels of the Illinois River from before 1900 to the 1966-1969 period. Note that some of the formerly common kinds of mussels were not taken alive in the 1966-1969 period. The possible additional ranges of the mussels were based on the author's opinion and were not substantiated by records. 342 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 that during the past three-quarters of a century 25 kinds of mussels have been extirpated from the Illinois River and its adjoining bottomland lakes (Tables 5, 9, and A-3)\ Data presented in the preceding section indicated that most of these mussels were not eliminated from the river until after 1912 (Fig. 9). How- ever, by 1912 the distribution of most of the mussels had been reduced, and since 1912 further reductions have oc- curred in the distribution and abundance of most of the surviving kinds of mus- sels in the river (Fig. 10). Five {F. ehena, A. suborbiculata, O. olivaria, T. donaciformis, and C. parva) of the 24 kinds of living mussels taken in the present study were represented by only single specimens. In this section the author has at- tempted to recapitulate the effects that domestic, industrial, and agricultural pol- lution have had upon the mussel fauna of the various parts of the Illinois River since the 1870-1900 period. Untreated domestic and industrial wastes were be- ing emptied into the river and its tribu- taries before 1900. In 1900 the pollution load of the river was increased greatly following the opening of the Chicago Sanitary and Ship Canal. No doubt, some species of mussels had been af- fected adversely by pollution in certain localities of the river even before 1900. Upper River The upper Illinois River as designated here extends from its source at the con- fluence of the Des Plaines and Kanka- kee rivers (river mile 272.9) downstream to the Starved Rock dam (river mile 231.0) near Utica (Fig. 1). This upper portion of the river encompasses the lower 1.4 miles of the Dresden pool, the Marseilles pool, and the Starved Rock pool. In the 1870-1900 period there were at least 38 different kinds of mussels living in the upper river (Table A-21), whereas in 1966 none were collected The author was aware o<=*the possibility that one or more rare species may have been missed in the 1966-1969 study; however, for purposes of this paper he has treated any kind of mussel formerly occurring in the river but not taken alive during the 1966- 1969 period as having been extirpated from the there. In the early 1870's Calkins (1874: 11) found that: "At the Starved Rock and in its vicinity, the river, here shallow, is literally filled with clams lying half buried in the sandy bottom." Since 1933 this section of the river has been impounded by the Starved Rock dam. A drastic change began to occur in the river in 1900 following the open- ing of the Chicago Sanitary and Ship Canal. Lake Michigan water, laden with sewage and untieated industrial wastes from the Chicago area, flowed into the Des Plaines River and thence into the upper Illinois, a distance of about 57 river miles from Chicago. In 1909 Wil- son & Clark (1912:34) noted that: "The Des Plaines River, which joins the Kankakee to form the Illi- nois River, is simply an immense sewer bringing down the Chicago drainage. Both rivers, but especially the Des Plaines, are full of the char- acteristic algae and other vegetation which grow in such waters, and the combination of a copious vege- tation with the sewage has effec- tually killed off all the mussels in the vicinity. Not a single living specimen could be found in either river, but there were hundreds of dead shells along the banks, most of them old and well bleached but still capable of identification." In 1912 in the vicinity of Morris (63 river miles from Lake Michigan) Forbes & Richardson (1913:517) found no mussels living in the heavily polluted mainstream; however, they did take seven species of dead mussels there. A little farther downstream they (1913: 518) observed that : "In midsummer, 1911, the water at the Marseilles dam had a gray- ish look and a disagreeable odor, but with perceptibly less material in suspension than at Morris." Forbes & Richardson (1913:525) in 1912 reported that at about 7 miles be- low the Marseilles dam at Ottawa there was a lessening of contamination. They stated that: "Diligent use of the crow-foot Feb., 1971 Starrett: Mussels of the Illinois River 343 dredge in various situations brought to light no living mussels except on a bar in Fox River water just out- side the mouth of that stream. Here two species were obtained alive — Lampsilis ventricosa and L. laevis- sima—and dead shells of eight other species. . . . The number of dead shells of both Unios and univalves, as compared with the living speci- mens found, was indicative of an en- vironment still difficult for mol- lusks." By 1912 pollution had virtually elim- inated the mussel population of the river in the vicinity of Starved Rock (Forbes & Richardson 1913:527-528). From this part of the river in the early 1870's Calkins (1874) collected 35 kinds of mussels (recognized by the present au- thor), whereas in 1912 Forbes & Rich- ardson (1913:528) found living speci- mens there of only two species of mus- sels (A. plicata and L. complanata) . During the summer months dissolved oxygen in the upper river in the 1911- 1928 period was extremely low, ranging from 0.1 to 0.9 ppm (Mills, Starrett, & Bellrose 1966:9). Probably the upper river's low dissolved oxygen content was an important factor reducing the mus- sel popuation during at least the first part of this century. As indicated in Table A-2 and Fig. 11, the dissolved oxygen in the upper river is now rela- tively high as compared to that of the 1911-1928 period, except possibly fol- lowing a heavy rainstorm in the Chicago area. During such a storm the capacities of the combined interceptor sewers and of the treatment plants may be exceeded, and polluted waters are then discharged into the waterway. Forbes & Richardson (1913:507) de- scribed the deplorable condition of the upper river at Morris in 1912: "The water here was grayish, slop- py, and everywhere clouded with tufts oi Sphaerotilus and Carchesium. The odor was continuously foul, with a distinct privy smell in the hottest weather. Bubbles of gas were continually breaking at the surface from a soft bar of sludge .... On the warmest days putrescent masses of soft, grayish black, mucky matter, from the diameter of a walnut to that of a milkpan, were floating on the surface." In 1966 the water at Morris and down- stream from there had the appearance of that of a relatively clean stream. The water had only a slight chemical odor but not enough to deter the use of the river here by boaters, water skiers, and some bathers. However, the bacterial counts (Table A-1) indicated that the entire river in 1966 was unfit for swim- ming. The vast improvements which have occurred in the dissolved oxygen content and the putrid condition of the upper river since the 1912-1928 period are, according to Mills, Starrett, & Bellrose (1966:9), a result of "the construction and operation of the trernendous sewage treatment plants by the Chicago Sanitary Dis- trict through a program instituted in 1922, and the lock and dam system built in the 1930's which slowed up the movement of the water. The adoption of better water pollution laws by the state also had its effect." The improvement in the treatment of domestic and industrial wastes in the past two decades by the cities along the Des Plaines, Kankakee, and upper Illinois rivers also has helped to reduce the biochemical oxygen demand in the upper Illinois. In spite of the ameliora- tion in the dissolved oxygen content and the appearance of the water during the past 40 years, the upper river still provides a poor environment for fish and mussel life (Fig. 10 and 11; Tables 10 and A-3) (Mills, Starrett, & Bellrose 1966:11-13 & 14-17). As mentioned earlier, no living mussel was taken in the upper river in the 1966 survey. This indicated that the upper river has remained unsuitabe even for reestablishing populations of mussel spe- cies possessing some tolerance to pollu- tion. Such tolerant mussels are living only a short distance downstream in the Peoria pool (Table A-3). The dissolved oxygen determinations and crowfoot bar catches for the entire river (Fig. 11) 344 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 indicated that in 1966 mussels were liv- ing in the lower La Grange pool in water containing less dissolved oxygen than was observed in the upper river. The determinations of the maximum amounts of ammonia nitrogen (N) cited in this study were made in 1967 (Allan Poole, pers. comm., 11 March 1968). MILES FROM LAKE MICHIGAN 327 307 267 267 247 227 207 187 167 147 127 107 87 67 47 37 ^/ \ ' LmBSflL MINIMUM DISSOLVED OXYGEN [SUMMER) MILES FROM MISSISSIPPI RIVER Hg. II.—Maximum amounts ot ammonia nitrogen (N) and dissolved oxygen in the Illinois River and numbers of mussels caught per 5 minutes of fishing with the crowfoot bar in the 1966 survey. The ammonia nitrogen (N) determinations were furnished by Mr. Allan Poole (pers. comm.. It March 19681. The 1965 and 1966 dissolved oxygen determinations were made from water samples taken 3 feet below the surface of the river in the navigation channel by the author. Increases in the dissolved oxygen content of the river are apparent below the various navigation dams and in Peoria Lake. The 1 966 crowfoot bar catches, expressed on a unit-of-effort basis, reflect the relative abundance of mussels in various parts of the river. (Mussels in Lower and Middle Peoria lakes were found to be more abundant than crowfoot bar collections indicated.) The steady upstream decline in the mussel population in the La Grange pool in 1966 apparently was associated with pollution from the Peoria-Pekin metropolitan area and in the upper part of the river with pollution from the Chicago-Joliet area. About I mile above Peoria (river mile 162.0) the mussel population increased markedly. Note the decline in the mussel population atid the increase in ammonia nitrogen (N> upstream from Middle Peoria Lake. Feb., 1971 Starrett: Mussels of the Illinois River 345 Table 10.—Numbers of kinds of mussels occurring in the navigation pools of the Illinois River proper in the 1870-1900 period, in 1912, and in the 1966-1969 period. Navigation 346 Illinois Natural History Survey Bulletin \'o1. 30, Art. 5 Table 1 1 .—Average numbers of common host fishes of mussels caught per 30 minutes of electrofishing in the navigation pools of the Illinois River (1962-19661. Kind of Fish Alton Pool La Grange Peoria Starved Rock Marseilles Pool Pool Pool Pool Channel catfish Freshwater drum Sunfishes (Centrarchidae)" 3.73 Feb., 1971 Starrett: Mussels of the Illinois River 347 and Middle ) and Lower Peoria lakes (about 1.5 miles average width). The river here is two lakes for 16.4 miles of the navigation channel except at the Peoria Narrows (Fig. 13) where an al- luvial fan separates the lakes. At Peoria the river constricts to a normal width of about 0.17 mile and continues 5.2 miles do\vnstream to the Peoria dam. Since 1870 at least 41 kinds of mussels (Table A-21) have been known to occur in the Peoria pool (73.4 miles long). In the 1966-1969 period 16 kinds of mus- sels were found living in the Peoria pool. However, in the upper 56.1 miles and lower 1.9 miles of this pool living mus- sels \vere relatively scarce as compared with the numbers found in the remainder of the pool (Table A-3 and Fig. 11). The extirpation of 25 kinds of mussels to- gether with reductions in the distribution and abundance of the surviving kinds probably occurred here mainly after 1912 rather than before, as was the case in the upper river. Starved Rock Dam to Chillicothe. — Between 1871 and 1900 some pollutants from Chicago were coming into the Illi- nois River at La Salle (Fig. 1) through the Illinois and Michigan Canal (Kofoid 1903:201-202; Walker 1956:6). Con- cerning pollution in the Starved-Rock- dam-to-Chillicothe section of the Peoria pool in 1911 and 1912, Forbes & Rich- ardson (1913:543-544) reported that: "It was at Spring Valley, fifty-seven miles below the mouth of the Des Plaines, that, in summer time, the last visible symptoms of water pol- lution were to be seen. The water here had not yet recovered its nor- mal slightly greenish tint, but was still grayish with suspended specks of septic and pollutional plankton; and it still smelled slightly of sewage, in part no doubt because of local contamination from Peru and La Salle, a few miles above. ... A con- siderable variety of aquatic insect larvae, of living mussels, and of gas- tropod mollusks, and a much smaller proportion of dead shells, testified further to an improved environ- ment. . . . At Hennepin it may be fairly said that virtualy normal conditions were found, except for the state of the bottom in winter time; although it must be confessed that our chemical data, especially those for the mid- Fig. 13.—The Peoria Narrows, separating Upper (Middle) and Lower Peoria lakes Upstream beyond the Narrows is Upper (Middle) Peoria Lake. Photo by the author. 348 Illinois Natural History Survey Bulletin \'oI. 30, Art. 5 summer low-water of 1911, were hardly consistent with this state- ment. . . . Henry to Chillicothe. — In this, the last section of the upper Illinois systematically studied by us in 1911 and 1912, the process of renovation is simply carried a little farther on than in the Henry-to-Hennepin sec- tion just above. It is only in the winter time that the effects of pol- lution are manifest here to the senses . . . ." By 1915 the river from Chillicothe upstream had unwholesome conditions in the bottom muds (Richardson 19216: 33). In 1912 Richardson (1928:456) determined the dissolved oxygen to be about 3 ppm at Chillicothe, whereas in the early 1920's zero was the usual lower limit of oxygen at this site. According to Forbes & Richardson (1919:145): "More recent evidence of a still continued gradual creeping down- stream of pollutional conditions is found by comparison of collections made in 1911 with those obtained in August, 1918. In the former year a foul-water fungus [Sphaerotilus natans) disappeared from both channel and shore at or near Starved Rock, while August 28 to 30, 1918, it was found in the river at Henry, 35 miles below Starved Rock, and also at Lacon, 6 miles still farther down." During the 1914-1925 period evidently pollution was so severe in the Starved- Rock-to-Chillicothe section that all of the mussel life \\as eliminated. Richardson's Table XXI (1928:457) indicated that in the 1924-1925 period he took no live mussel above Upper Peoria Lake (Table 12). The increase in pollution after 1912 in this section of the river as well as farther downstream was related to sev- eral factors which developed in the Chi- cago area. In the 1914-1920 period, according to Richardson (1928:398): "the Chicago population is estimated to have increased around 10 per cent, to about 2,701,000; and the stock yards wastes, in population equivalent equal to 1,040,000, were about 19 per cent greater than in 1914, after having fallen off 353,000 since the peak of the war-time ac- tivity of 1918. Between 1914 and 1920, all of the wastes from the sources above described were re- ceived by the Sanitary Canal and Illinois River wholly untreated and subject after delivery only to the effects and processes of dilution and biological purification, varying with river levels, temperature, and other physical conditions, as chance might offer." Other untreated wastes from the Chicago area in this period were estimated by Richardson (Ibid.) to have had an addi- tional population equivalent of about 500,000. In the 1920's the additional sewage from the expanding human population' of the Chicago area began to be affected by the treatment of sewage and the re- duction of certain industrial wastes en- tering the canal (Richardson 1928:399). By 1960 the wastes before treatment in the Chicago metropolitan area had a population equivalent of 9.50 million, but after treatment they amounted to a population equivalent of only 1.15 mil- Table 12.—Numbers of kinds of mussels living in various parts of the Peoria navigation pool of the Illinois River in 1912, the 1924- 1925 period, and the 1966-1969 period. Feb., 1971 Starrett: Mussels of the Illinois Ri\er 349 lion ( United States Public Heath Service 1963: 1 1 1-3). This fact indicated a re- duction of about 77 percent since 1918 in the wastes entering the Illinois River waterway from the Chicago area. This is a remarkable engineering achievement, for the population equivalent of wastes before treatment in 1960 was about double the population equivalent of 1918. In the 1966 survey 32 living mussels were taken in the Stai-ved-Rock-to-Chil- licothe section of the Peoria pool (Table A-3). Ten different kinds of mussels were represented in these collections of which 50.0 percent were three-ridges {A. plicata) and floaters [A. g. corpulenta) . The presence of living mussels in 1966 in this section of the river indicated an improvement in conditions for mus- sels since the 1918-1925 period. The dissolved oxygen content of the river in the lower part of this section of the Peoria pool tended to be quite low in midsummer (Fig. 11); however, the au- thor has never recorded zero readings as did Richardson (1928:456) at Chil- licothe in the early 1920's. The maxi- mum detemiinations of ammonia nitro- gen (N) (range 3.4-6.0 ppm) in this section of the river did not exceed 6.0 ppm in 1967 as they did in the upper river where no living mussel was taken in 1966 (Fig. 11). The range of maxi- mum total phosphates (PO4) in this section of the river in 1967 was 2.5-5.5 ppm. La Salle-Peru.—In 1912 Forbes & Richardson (1913:529) collected mus- sels between Utica and Peru with a crowfoot bar and ^v•rote that: "The large proportion of dead spe- cimens, as compared with the ratios obtained farther down the stream, indicate unfavorable conditions for mussels in the stretch of river be- tween Utica and Peru." A comparison of the numbers and kinds of mussels taken in 1912 and 1966 was made in Table 13. Two of the four kinds of mussels taken in 1966 in this area were also collected there by Forbes & Richardson. With the exception of the mucket (A. ligamentina) , the other spe- cies taken alive there in 1912 were found a short distance downstream in 1966. The mucket was not collected alive any- where in the Illinois River in the present Table 13.—Numbers and kinds of mussels taken alive and dead in the LaSalle-Peru area of the Illinois River in 1912 and 1966. Mussels Taken Kind of Mussel F. ebena (Ebony Shell) A. pltcata (Three-Ridge) Q^. pustulosa (Pimple-Back) Quadrula sp. L. complanata (White Heel-Splitter) A. g. corpulenta (Floater) S. undulatus (Squaw Foot) 0. reflexa (Three-Horned Warty-Back) A. ligamentina (.Mucket) L.jragdis (Fragile Paper Shell) P. alala (Pink Heel-Splitter) /.. a. i. fallaciosa (Slough Sand-Shell) L. ventrkosa (Pocketbook) 350 Illinois Natural History Survey Bulletin \^oI. 30, Art. 5 study, and the author was surprised to learn that this species was able to survive the poor conditions existing for mussels in this part of the river in 1912. A floater [A. g. corpulenta) was col- lected just below Utica at river mile 229.3, the farthest upstream point where a live mussel was taken in 1966. In the La Salle- Peru area the maximum am- monia nitrogen (N) determination in 1967 was 6.0 ppm (Fig. 11), and as was shown in Table 13, a few specimens of four kinds of mussels were able to \vithstand this high concentration of am- monia nitrogen for at least a short time. The author has found that the midsum- mer dissolved oxygen content of the river in this area usually has been over 4.5 ppm ( Fig. 11). The relatively high oxy- gen content of the river here is caused by the \vater mixing with the air as it falls over the Starved Rock dam just upstream from the La Salle-Peru area. As has been discussed for the upper river, the author does not consider dissolved oxygen a limiting factor for mussels in the La Salle-Peru section of the river. Hennepin.—In the Hennepin area in 1912 Forbes & Richardson (1913:533) collected 187 living mussels of 17 differ- ent kinds (Fig. 9). These collections in- cluded in part 60 slough sand-shells (L. a. f. fallaciosa) , 45 three-ridges [A. pli- cata) , 23 white heel-splitters (L. com- planata) , 14 floaters {A. g. corpulenta) , and 11 washboards {Al. gigantea). In 1966 only one live three-ridge [A. pli- cata) was taken in this part of the river. Henry.—Forbes & Richardson (1913: 533 & 536) and Danglade (1914:37) reported taking 24 different kinds of live mussels in the Henry area in 1912, but in 1966 only 9 kinds were collected alive there (Table A-22). Danglade (1914:14) took 128 living mussels there in 1 hour of fishing with a crowfoot bar, whereas in 3 hours of similar fishing in 1966 only 4 live mussels were caught (Table 14). The comparison in Table 14 of crowfoot bar catches made in 1912 and 1966 clearly reflected the impact of pollution on the mussel population in this part of the river during the inter- vening 54 years. Chillicothe.—From the ri\er near Chil- licothe in 1912, Forbes & Richardson (1913:533 & 536) and Danglade (1914: Table 14.—Numbers and kinds of live mussels taken with the crowfoot bar in the Illinois River in the vicinity of Henry in 1912 and 1 966. Kind of .Mussel Mussels Taken in 1 Hour of Fishing in 1912" Mussels Taken in 3 Hours of Fishing in 1966^ F.f. f. undata (Pig-Toe) M. gigantea (Washboard) A. pltcata (Three-Ridge) Q. quadntla (Maple-Le,af) Q. puslulosa (Pimple-Back) T. verrucosa (Buckhorn) E. dilatatus (Lady-Finger) A. confragosus (Rock Pocketbook) L. complanata (White Heel-Splitter) A. g. corpulenta (Floater) S. undulatus (Squaw Foot) A. ligamtntina (Mucket) T. truncata (Deer-Toe) L./ragilis (Fragile Paper Shell) P. alata (Pink Heel-Splitter) L. a. i. fallaciosa (Slough Sand-Shell) Total 5 4 70 2 5 1 1 2 2~~ 2 I 25 1 4 2 1 •Danglade (1914:14). The collection may have been made ir has used only the 1912 date. ^ Present survey. Collections from river miles 190.0-199.3. '' This mussel was taken here in 1966 either by dredging either by dredirinK or wailing were A. g. arnndia (Floater). A laeviaeima (Fragile Heel-Splitter). 1911; however, in this paper the author Feb., 197! Starrett: Mussels of the Illinois River 351 37 ) repotted collecting 28 different kinds of mussels (Table A-22). Danglade (1914:15) caught 223 mussels with a two-bar haul over the lower end of a productive mussel bed located just above Chillicothe. Part of his catch included 83 three-ridges {A. plicata) , 25 fat inuckets (L. r. luteola) , 24 washboards (AI. gigantea), 22 lady-fingers [E. dila- tatus) , 17 pimple-backs (Q. pustulosa) , 17 pig-toes (F. /. f. undata) , and 12 muckets {A. ligamentma) . Danglade (Ibid.) mentioned that in earlier years 10—12 ebony shells [F. chena) had been caught per haul from this bed by com- mercial clammers, whereas in 1912 only an occasional ebony shell was taken. Probably by 1918 this mussel bed had been wiped out by pollution, and ap- parently conditions have never been fa- vorable enough since for the bed to be- come reestablished. In this area in 1966 the only living mussels taken were five thrce-ridgcs [A. plicata) and one slough sand-shell (L. a. f. fallaciosa) . Peoria Lake.—The mussel life in the broad expanse of Peoria Lake between Chillicothe and Peoria was described in 1911 and 1912 by Danglade (1914:14) : "The slow current, the large volume of water, the good average depth and soft mud bottom are suitable for mussel growth, and there are consecjuently many fine mussel beds and an enormous quantity of shells, making this at present probably one of the best mussel-producing dis- tricts in the United States." During that period at least 35 different kinds of mussels lived in Peoria Lake (Table A-23). Between the 1913-1915 period and 1920 pollution had virtually eliminated the former normal bottom animals of the river between Chillicothe and Beards- town, including those of Peoria Lake (Richardson 1925fl:327). This en- croachment of pollution from upstream and its effects on the mussel life of Peoria Lake were described by Richard- son (1928:454) : "The mussels died out rapidly in all three sections of the lake during and after 1917 until commercial clamming entirely ceased because of failure to obtain shells. In the sum- mer of 1920 a single clammer oper- ated a bar for a few days in the channel of the Lower Lake opposite the center of Peoria, but took noth- ing but dead shells except for an occasional live specimen of Am- hlrma rariplicata or still less fre- quently Quadrula pustulosa. In 1920-1922 the Natural History Sur- \ey took single examples of three species {Amblcma rariplicata, Ano- donta imbecillis, and Quadrula pus- tulosa) . . . . Commercial clamming on a scale much reduced from that of the pre- 1920 period began again in 1924 and has been continued s[)oradicall\- by a few clammers since. The only commercial species obtained since then in salable quan- tity, however, has been the common three-ridge, Amblema rariplicata." Dr. Morrison (pers. comm., 12 August 1969 and 6 March 1970) wrote that there was very little mussel life in Peoria Lake in 1931 and that he took only three living mussels there. In this study 12 different kinds of mussels were taken alive in Peoria Lake, indicating that at least 23 kinds had been extirpated from this part of the river since 1912 and 4 since the 1924- 1925 period (Tables A-3, A-23, and 15). Richardson (1928:455) considered Upper Peoria Lake as two separate lakes —Middle Peoria Lake (river miles 167.2- 174.9) between the Peoria Narrows and Spring Bay, and Upper Peoria Lake (riv- er miles 174.9-179.7) from Spring Bay to below Chillicothe. The author has fol- lowed Richardson's division of Upper Peoria Lake into two lakes in order to compare his 1924-1925 mussel collections with those made in the present study ( Table 15). Even though his division of Upjjcr Peoria Lake into two lakes was artificial, this separation was useful in treating the 1966 data of tliis lake. Ap])arcntly Upper Peoria Lake as des- ignated here with its broad expanse of water and virtual absence of current tended to serve as a partial recovery zone for the river. The dissolved oxygen curves shown in Fig. 1 1 clearly indicated a sharp increase in the dissolved oxygen 352 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Table 15.— Kinds of mussels present in Peoria Lake in the 1924-1925 and 1966-1969 periods." Kind of Mussel Mussels in Peoria Lake Upper Middle and Lower 1924-1925 1966-1969 1924^1925 1966-1969 F.J. f. undata (Pig-Toe) M. gigantea (Washboard) A. plicata (Threc-Nidgc) Q.. quadruta (Maplc-Lcaf) (2- puslulosa (Pimple-Back) E. dilatatus (Lady-Finger) A. conjragosus (Rock Pocketbook) L. complanala (White Heel-Splitter) A. g. grandis (Floater) A. g. corpulenla (Floater) A. imbecllis (Paper Pond Shell) A. suburbiculata (Hecl-Splitter) 0. reflexa (Three-Horned Warty-Back) L.fragilis (Fragile Paper Shell) P. alala (Pink Heel-Splitter) P. laevissima (Fragile Heel-Splitter) C.parva (Liliput Shell) L. a. f./allaciosa (Slough Sand-Shell) L. r. luteola (Fat Mucket) Total Richardson (1928:456), 1966 survey, and 1969 commercial data. ^ P denotes present and A designates absent. •^ Taken by commercial fisherman in 1969 from the Illinois River just below Peoria Lake. content of the river at the upper end of Middle Peoria Lake (river mile 174.9) . Likewise, in coming downstream in the 1966 survey the first relatively large- sized population of mussels was encoun- tered in Middle Peoria Lake ( Fig. 1 1 and Table A-3). In Upper Peoria Lake in 1966 only 6 live mussels of 3 species were collected, whereas in Middle Peoria Lake 533 live mussels of 1 1 different kinds were taken. In the 1924-1925 period Richardson ( 1928:455) collected eight kinds of mus- sels from Up]3er Peoria Lake, all taken at its lower end. Richardson (Ibid.) was of the opinion that the 1 1 species of mussels he took in the 1924-1925 period in Middle Peoria Lake (Table 15) probably had remained "through the worst of the wave of pollution that destroyed the more sensitive Mollusca about ten years ago." In the 1924-1925 period Richardson (1928:455) collected the liliput shell (C. parva) in Middle Peoria Lake and the three-horned warty- back {O. rejle.xa) in both Middle and Lower Peoria lakes. In 1966 both of these species were confined to the lower part of the river. Evidently the adults of these species were able to withstand the severe pollution in Peoria Lake dur- ing the period of World War I but were unable to maintain populations in subse- cjucnt years. In 1966, beds comprised largely of three-ridges {A. plicata) were found in Middle and Lower Peoria lakes, and these beds were extensive enough to in- terest comnicrcial mussel fishermen. No commercial fishing had been conducted in the Peoria pool for a number of years prior to 1969. In that year com- mercial mussel fishermen removed about 100,000 pounds of mussels (10 percent dead shells) from Lower and Middle Peoria lakes; however, 85,941 pounds (10 percent dead shells) of these mus- sels were dredged from one bed at river Feb., 1971 Starrett: Mussels of the Illinois River 553 mile 164.1 (LB) in Lower Peoria Lake (Webb Moss, pers. comm., 30 October 1969). They also found mussels occur- ring abundantly in Middle Peoria Lake but did little fishing there in 1969. The 1966 survey data and the above com- mercial statistics indicated that mussels were much more abundant in Middle and Lower Peoria lakes in the 1966-1969 period than they were in the 1918-1931 period. The author is of the opinion that through the years natural selection has played an important role in re- establishing the mussel beds in Peoria Lake. Improved treatment of municipal and industrial wastes in the Chicago area and elsewhere along the upper Illi- nois River waterway have also undoubt- edly helped to improve Peoria Lake as a mussel habitat. However, conditions had not improved enough in Peoria Lake to permit the reestablishment of 23 kinds of mussels known to have lived in this part of the river in 1912. Foot of Peoria Lake to Peoria Dam. — The Illinois River abruptly narrows at Peoria and flows downstream 5.2 miles to the Peoria lock and dam. A power plant (fossil fuel) is located on the left bank of the upper end of this section of the river, and it has not been determined what effect the heated discharge from this plant has on mussel life in this section of the river. However, on the left bank of the upper part of this section of the river (river miles 161.1-162.3) occurred the largest standing crop of living mussels found in the entire river in the 1966 survey (at river mile 161.6 total phos- phates were 5.7 ppm, and ammonia ni- trogen was 3.0 ppm) . The estimated standing crop here in 1966 was 6,040 pounds (live weight) of mussels per acre. The three-ridge {A. plicata) comprised 85.3 percent of the mussels taken here in the 1966 survey. In 1969 commercial mussel fishermen removed from these un- fished waters 108,500 pounds (live weight) of mussels (Webb Moss, pers. comm., 30 October 1969). In the 1966- 1969 period 11 kinds of mussels were collected from the U[jj)er part of this section of the river, including the pimple- back {Q. pustulosa) and the buckhorn (7". verrucosa). Conditions evidently were better here for mussels than they were in Middle and Lower Peoria lakes; however, the differences were not as great as was indicated by the 1966 crow- foot bar catch data shown in Fig. 1 1 . Catches in Peoria Lake would have been much higher had there been more cur- rent there (the current is not perceptible in Peoria Lake at normal pool stage), since the crowfoot bar is less efficient in slack water than in moving water. No sampling was done in this section between river miles 160.0 and 161.1. The lower part of this section of the river (river miles 158.1-160.0) was be- low the outlets of the treated sewage and industrial effluents from East Peoria and Peoria. The demarkation between the upper and lower parts of this section of the river was reflected by a sharp decline in the mussel population (Fig. 11). In the upper part of this section of the river (river miles 161.1-162.3) the crowfoot bar catch was 1 1 .0 mussels per 5 minutes of fishing, whereas in the lower part the catch was only 0.2 mussel per 5 minutes of fishing (Fig. 11 ; Table A-3). In 1966 wastes from East Peoria received only primary treatment. The city of Peoria has had a modern sewage treatment plant (river mile 160.2) for a number of years, and in the late 1960's it began tertiary treatment. In 1966, according to Mr. ELdwin Fall of the (ireater Peoria Sanitary District (pers. comm., 24 February 1969), the untreated wastes coming into the Peoria treatment |)!ant had a ]30]3ulation equivalent of 381,000, but the treated wastes going into the river had a population equiva- lent of 57,000. La Cirangc Pool The additional pollution load dis- charged into the river from the Peorta- Pekin area had a noticeable effect upon the mussel life in the upper ])art of the La fJrangc ])ool in 1966 (Fig. 11). In 1 960 the estimated BOD load discharged into the river from industrial sources in the Peoria-Pekin area had a popula- 354 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 tion equivalent of 386,000 (United States Public Health Service 1963: 111-5). Mr. Edwin Fall (pars, comm., 24 February 1969) informed the author that the estimated population equivalent of treat- ed and untreated domestic and industrial wastes entering the river in 1960 from Peoria was about 100,000, but as in- dicated above, this has been reduced considerably since 1960. The remaining 150 miles of the river from Pekin to Grafton received only agricultural runoflf and effluents from small communities and a few small industries. Kofoid (1903:198-203) reported that in 1897 sewage from Chicago entering the Illinois River through the Illinois and Michigan Canal at La Salle and from the Peoria-Pekin area was one of the most important factors causing an abundance of plankton in the Havana area. Apparently pollution did not be- come detrimental to aquatic life in the La Grange pool until after 1915 (Rich- ardson 1921&:49). Richardson (1925&: 411) limited his collecting to small bot- tom fauna organisms in the La Grange and Alton pools, and as a result, the effects of pollution in the 1915-1920 pe- riod on mussel life in these pools were not recorded. Between the 1913-1915 period and the summer of 1920 the dis- solved oxygen at Havana dropped from 4 ppm to 1 ppm (Richardson 1925a: 327-328). During this period pollution eliminated about 70 kinds of benthic organisms other than mussels from the river near Havana and 24 or more kinds between Havana and Beardstown (Rich- ardson 1925^:410-413) (Fig. 14). In 1917 Richardson (1925a: 329) observed a heavy mortality of snails in various parts of the river between Spring Valley and Havana. Between 1870 and 1912 at least 43 different kinds of mussels were known to have occurred in the mainstream of the La Grange pool (Table A-21), whereas only 18 kinds were collected alive from the mainstream of this pool in 1966 (Table A-3). No doubt this drastic reduction in the mussel fauna of this pool occurred largely in the 1915- 1920 period simultaneously with the de- struction of other benthic organisms by domestic and industrial pollution from Chicago and the Peoria-Pekin area as described by Richardson (1921a, 192 It, 1925a, 1925fo, and 1928). Silt pollution probably also has affected certain species of mussels in the La Grange pool, such as the yellow sand-shell (L. a. f. ano- dontoides) . Peoria Dam to Havana.—In 1912 Danglade (1914:17) found five mussel beds between Peoria and Pekin and sev- rig. 14.—The Illinois River at Beardstown, showing a towboat moving upstrean section of the river is in the La Grange navigation pool. Photo by the author. Feb., 1971 Starrett: Mussels of the Illinois River 355 eral beds between Pekin and Havana. No mussel bed was detected in this sec- tion of the La Grange pool in 1966. Danglade ( 1914: 18) determined the spe- cies composition of mussels in the Liver- pool area of the river (between Pekin and Havana) in 1912 to be 36 percent three-ridges (A. plicata) , 30 percent pimple-backs (Q. pustulosa) , 5 percent washboards (M. gigantea) , 4 percent muckets {A. ligamentina) , 8 percent oth- er commercial shells, and 17 percent noncommercial shells. In that area in 1966 only 36 living mussels of the fol- lowing kinds were collected : 22.2 percent maple-leafs (Q. quadrula) , 13.9 percent three-ridges [A. plicata), and 63.9 per- cent noncommercial species (Table A-3). In the mainstream of the river between the Peoria dam and Havana 32 kinds of mussels were taken in 1912 by Dan- glade (1914:37), whereas only 11 kinds were collected from this section in 1966 (Table A-24). The 1966 collections from the mainstream of this section did not include five kinds of mussels taken alive that year in Quiver Lake (Table A-24). As has been mentioned earlier, Quiver Lake, located just above Havana, is merely a slough connected with the river. The lower part of the lake is a large expanse of the river. Natural springs on the bluff side (LB) of this lake evidently provided a more suitable habitat for mussels than did the main- stream; however, the species taken in Quiver Lake were collected in the river farther downstream. Below Havana to La Grange Dam. — The size of the mussel population in 1966, as reflected by the crowfoot bar catches shown in Fig. 11, increased steadily as we proceeded downstream from below Havana (river mile 120.0). In 1966 a few washboards (M. gigan- tea) , pimple-backs {Q. pustulosa) , warty- backs (Q. nodulata), and deer-toes (T. truncata) appeared in the collections made in this section of the river (Fig. 10). As the data in Fig. 1 1 indicate, the increase in the abundance of mussels in the lower part of the La Grange pool was accompanied by slight decreases in the maximum amounts of ammonia ni- trogen (N) . However, in this section of the pool the dissolved oxygen in mid- summer sometimes becomes quite low (Table A-2 and Fig. 11). Low dissolved o.xygen content and heavy siltation may have been important factors contributing to the loss of certain species of mussels since 1912 in this section of the river. The 1966 collections indicated that the mussel population there included 67.0 percent three-ridges {A. plicata) and 13.2 percent maple-leafs (Q. quadrula). These two abundant species the author considered somewhat tolerant of pollu- tion and siltation. In 1912 Danglade (1914:19-20) found pimple-backs (Q. pustulosa), washboards [M. gigantea), lady-fingers {E. dilatatus) , and three-ridges {A. pli- cata) the most abundant species in this section. These species, excepting the lady-finger, were among the most abun- dant species found on downstream in the Alton pool in 1966 (Fig. 10; Tables 6, 7, and A-3). Another apparent effect of pollution and siltation in the lower La Grange pool since 1912 has been the extirpation of 23 different kinds of mus- sels (Table A-25). Alton Pool During the past three-quarters of a century 21 different kinds of mussels have been extirpated from this lower 80.2 miles of the river (Tables A-3 and A-21; Fig. 15). Concerning conditions in the Alton pool in 1912, Danglade (1914:7) commented: "Whether or not the great amount of sewage that is annually poured into the river is detrimental to the aquatic life in the lower stretches, the fact remains that from Chilli- cothe to near the mouth, with few e.xccptions, the Illinois is indeed a wonderfully productive stream in fishes and mussels, and far exceeds in these resources many rivers not having similar physical conditions." In 1912 Danglade (1914:21-25) noted that some of the mussel beds in the upper part of the Alton pool were "playing out," but in the middle and lower parts of this pool the beds were very produc- tive. Many of these beds were still pro- 356 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Fig. 15.—The Alton navigation pool of the Illinois River at Hardin. Photo by the author. ductive enough in 1966 to support a commercial mussel fishery. At least 38 different kinds of mussels were taken from this pool in 1912 by Danglade (1914:37), whereas only 20 kinds were collected there in the 1966 survey (Table A-3). However, fewer species have been eliminated from the Alton pool than have been extirpated elsewhere in the river during the past 54 years (Fig. 10). Also, in 1966 mussels were much more abundant there than they were in the other pools except for one small area just below Peoria Lake and in Lower Peoria Lake (Fig. 11). Only in the Alton pool were conditions suitable in 1966 for the support of relatively large- sized populations of pimple-backs {Q. pustulosa) and washboards (M. gigan- tea) and moderate-sized populations of warty-backs (Q. nodulata) and three- horned warty-backs [O. reflexa). The species composition and abundance of mussels in the Alton pool in 1966 clearly indicated that by the time the water reached this pool some semblance of re- covery in water quality had occurred although not enough to support the va- riety and numbers of mussels known to have existed there in 1912. Richardson (1921a: 405) noted that in the Alton pool: "Inside the 7-foot line in 1915 a soft light-colored silt 2 inches to more than 1 2 inches deep was found at most of our collecting stations." Siltation probably has limited the dis- tribution and abundance of such spe- cies as the yellow sand-shell (L. a. f. anodontoides) during the past 75 or more years in this pool. However, the prime limiting factor in the Alton pool prob- ably has been the effects of domestic and industrial pollution from upstream sources. A comparison of the collections of mussels made in the vicinity of Mere- dosia (river mile 71.2) between 1912 and 1966 indicated that the mussel fauna of the Alton pool was affected adversely by pollution between 1912 and 1930 but that conditions for mussels probably have worsened since 1930 (Table 16). Only single live specimens of the ebony shell [F. ebena), the fawn's foot {T. dona- ciformis) , and the liliput shell (C. par- va) were taken in the 1966 survey, and all of these were taken downstream from Meredosia. The paper pond shell [A. imbecillis) was not collected at Mere- dosia in 1966 but was taken just below there at Naples. In 1930 and 1955 the buckhorn (7". verrucosa) was present at Meredosia, but in the 1966-1969 period it was only taken farther upstream in the Peoria pool; however, the author believed that this species may still occur rarely in the Alton pool. The yellow sand-shell (L. a. f. anodontoides) was the only mussel taken in 1930 at Mere- dosia that was not collected alive from some location in the river during the 1966-1969 period (Fig. 10). This species Feb., 1971 Starrett: Mussels of the Illinois Riv^er 357 Table 16.—Kinds of mussels taken alive from the Illinois River in the vicinity of Mere- dosia in 1912, 1930, 1955, and 1966. Kind of Mussel Mussels Taken F. ebena (Ebony Shell) F.J. [. undata (Pig-Toe) M . gigantea (Washboard) A. plicala (Three-Ridge) Q^. quadrula (Maplc-Leaf) Q_. puslutosa (Pimple-Back) Q. nodulata (Warty-Back) Q_. metanevra (Monkey-Face) T. verrucosa (Buckhorn) C. tuherculata (Purple Warty-Back) P. cyphyus (Bullhead) P. coccuieum f. solida E. crassidens (Elephant's Ear) E. dilalatus (Lady-Finger) A. confragosus (Rock Pocketbook) L. complanata (White Heel-Splitter) A. grandis complex (Floater) A. imbecilUs (Paper Pond Shell) 0. reflexa (Three-Horned Warty-Back) A. Itgamenlma (Mucket) P. lineolala (Butterfly) T. truncata (Deer-Toe) T. donacijormis (Favvn's Foot) L. fragilis (Fragile Paper Shell) P.'alata (Pink Heel-Splitter) P. laevissima (Fragile Heel-Splitter) C. parva (Liliput Shell) L. recta (Black Sand-Shell) L. a. f. anodonloides (Yellow Sand-Shell) L. a. (.fallacwsa (Slough Sand-Shell) L. r. luteola (Fat Mucket) L, ventricosa (Pocketbook) L. 0. f. higgmsii (Higgin's Eye) Tolal pe ^58 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Table 17.—Organochlorine pesticides present in mussels collected from the Illinois River during August 1966." Kind of Mussel Feb., 1971 Starrett: Mussels of the Illinois River 359 was done above Beardstown near Brown- ing and Bath. However, in 1966 all mussel fishing was done in the lower 87 miles of the river between Beards- town and its mouth. This was the only known continuous stretch of the river containing a sufficient number of mussel beds large enough to attract commercial clammers in 1966 (Fig. 16). The loca- tions of the beds fished commercially in 1966 are given in Table A-26. In addition, three-ridges occurred abun- dantly enough in 1966 just below Lower Peoria Lake and in Lower and Middle Peoria lakes to have provided commer- cial fishing.' Considerable variation existed in the estimates of the standing crops of mussels in the commercial beds sampled with ' Commercial mussel fishermen removed 208.B00 pounds of shells from those waters in 1969 (Webb Moss. pers. comm.. 30 October 1969). Fig. 16.—Johnboats used by commercial mussel fishermen in the Alton navigation pool of the Illinois River in 1966. Photo by Alvin C. Lopinot. 360 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 the dredge in 1966 (Table A-27). These variations were probably the result of sampling errors, differences in the carry- ing capacities of the beds, and differences in fishing pressure on various beds. The estimates of the standing crops of mus- sels in two unfished beds in the Peoria pool (river miles 162.3 and 168.2) were thought by the author to give some indi- cation of the number of pounds per acre of commercial-sized mussels (height 2.5 inches or more) that might have been expected in the beds of the lower river in 1966 had they not been fished in recent years. The estimated standing crops of shells of commercial size in these two unfished beds in the Peoria pool were 536 pounds and 2,030 pounds per acre, whereas in the commercially fished beds of the lower river the standing crops of these shells ranged from 51 to 1,312 pounds per acre. These differences in standing crops suggested that many of the beds in the lower river had been heavily fished in recent years. Additional evidence of heavy fishing pressure in the lower river was reflected by size differences in the three-ridges {A. plicata) taken in the survey in the lower river (Alton pool) and the Peoria pool. The three-ridge was the most abundant commercial shell occurring in the river in 1966. In the survey collections in the Alton pool only 39.8 percent of the three-ridges taken (1,598 shells) were of commercial size, whereas in the un- fished Peoria pool 64.0 percent of the three-ridges taken (689 shells) were of commercial size. This highly significant difference in the sizes of the three-ridges between the pools was believed to be the result of the selective removal of the large, desirable, commercial-sized shells by commercial clammers. The growth rate of the threc-ridge was better in the Peoria pool than it was in the Alton pool, but it was not great enough to account for the differential in commer- cial-sized shells found in the two pools (Table A-13). In 1967 and 1968 little commercial mussel fishing was done in the Illinois River because of the lack of a market for the shells. The market for Illinois River shells picked up again in 1969. In the author's opinion, the mussel fishery should be carefully regulated to prevent overfishing. The fishery could be regu- lated by a Department of Conservation temporary administrative order restrict- ing mussel fishing in the river to a limited period during a year when a market demand for shells was anticipated. In slack years the fishery would regulate itself. Shell buyers should be required to furnish the Department of Conserva- tion with accurate statistics on the num- bers of tons purchased by them from Illinois River fishermen. Such statistics would be of value in making annual appraisals of the condition of the mussel fishery. The Japanese need relatively large, thick shells for the nuclei used in the culturing of pearls. Their buyers wanted only shells having a minimum height of 2.5 inches, and they preferred three- ridges and washboards of 3.0 inches or more in height. As was mentioned earlier, the mussel fishery on the Illinois River in 1966 depended largely upon the abun- dant three-ridge shell. In this study it was found that in the Illinois River the three-ridge did not attain the height of 2.5 inches until it was 10-12 years of age and that it required 18-20 years to attain a height of 3.0 inches (Table A-13). As a result of this slow growth, very few three-ridges having a height of 3.0 inches or more were found in the river (Table A-12). The washboard was not nearly as abundant as was the three-ridge, but because of its size, it was the second most important commercial shell occur- ring in the river (Table 18). In the Illinois River washboards attained a height of 2.5 inches within 7 years and a height of 3.0 inches within 9 years (Table A-11). In the 1966 survey col- lections 90.3 percent of the washboards taken had a height of 3.0 inches or more (Table A-10). Most of the washboards taken commercially were of the preferred Feb., 1971 Starrett: Mussels of the Illinois River 361 size : however, the bulk of the commercial fishery depended upon three-ridges hav- ing a height of 2.5-3.0 inches. There- Table 18.—Species composition of mussel shells in sorted commercial piles along the Illi- nois River at Meredosia and Kampsville in 1966. 362 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 species. In the sorted commercial shell piles examined by us in 1966 few species other than three-ridges and washboards were of commercial sizes (Table 18) . In the Illinois River very few maple-leaf and pimple-back shells attained a height of 2.5 inches or more (Tables 18, A-15, and A-16), and as a result, most of these shells taken by clammers were wasted because of their small sizes. In 1967 the Seventy-fifth General Assembly of Illinois passed a law making it un- lawful to take mussels in Illinois with shells less than 2.5 inches on the shortest line from the center of the hinge side and at a right angle across the shell to the outer edge (height). The enforce- ment of this law should reduce the for- mer wanton waste of mussels occurring in the Illinois River. Other new state regulations on mussel fishing specify the methods and kinds of equipment that commercial clammers may use to take mussels in the Illinois River. These are crowfoot bars, hand picking (wading), hand rakes, hand forks, and hand dredges. Wisely, these regulations prohibited the use of basket dredges, self-contained or ancillary air diving devices, and mechanical or suc- tion devices. Various analyses of the efficiency and selectivity of the methods of mussel fishing employed in the 1966 survey are contained in the appendix of this paper (Tables A- 10, A- 12, A-15, A-16, A-28, A-29, and A-30) . As indi- cated in these analyses, large numbers of small mussels were taken with the crowfoot bar and hand dredge. No at- tempt was made to determine the mor- tality of small mussels caught with the crowfoot bar or dredge and returned to the river. In our collections made by wading, mussels of all sizes were kept. However, commercial clammers using the wading method could be very selective in the sizes of mussels taken. Conservation and management plan- ners interested in the pearly mussels of the Illinois River should look beyond the mussels' value as a commercial re- source and consider that these organisms are an intricate part of the ecosystem of the river. The present study has dem- I onstrated that 25 kinds of mussels al- ready have been extirpated from the river by the effects of man's activities, and if remedial measures are not taken soon, others will also vanish. SUMMARY 1.—The Illinois River is 272.9 miles long and is formed by the confluence of the Des Plaines and Kankakee rivers southwest of Chicago. It empties into the Mississippi River at Grafton, Illinois. Since 1900 Lake Michigan water has been diverted through the Chicago Sani- tary and Ship Canal into the Des Plaines River and thence into the Illinois. Through the years this canal has trans- ported the treated and untreated wastes from the Chicago area into the Illinois River system. These wastes together with those from other cities, industries, and agriculture along the Illinois waterway have drastically affected the biota of the river. There were only minor sources of domestic and industrial pollution along the lower 150 miles of the river. Locks and dams, together with dredging, maintain a 9-foot navigation channel to form the Illinois waterway connecting the Mississippi River with Lake Michi- gan. 2.—A considerable amount of histori- cal biological and chemical data relative to the Illinois River has been published. These data, together with museum rec- ords, furnished the background for the present biological investigation. 3.—In 1966 a survey of the pearly mussels (Unionacea) of the Illinois | River was madfe. In this survey 4,247 j live mussels were taken in 429 collec- j tions from various parts of the river. I These collections were made with an [ exploratory crowfoot bar, with a dredge, and by wading. The largest estimated standing crop of live mussels found in the river was 6,040 pounds per acre. (Several live mussels were obtained from commercial mussel fishermen operating in the Peoria pool in 1969, and the rec- ords of these shells are included in the text.) Feb., 1971 Starrett: Mussels of the Illinois River 363 4.—Subfossil shell collections were made at 21 locations along the Illinois River in 1966. 5.—Twenty-four kinds of living mus- sels were taken from the Illinois River and its bottomland lakes in the 1966- 1969 period. Five species were repre- sented by single specimens. The three- ridge {A. plicata) was the most abun- dant mussel and made up 62.4 percent of the mussels collected. Mussels which were fairly common were the pimple- back (Q. pustulosa) , the maple-leaf (Q. quadrula) , the washboard {M. gigan- tea) , and the floater (A. g. corpulenta) . 6.—At least 49 different kinds of mus- sels were present in the Illinois River and its adjoining bottomland lakes in the 1870-1900 period. Since that pe- riod 25 kinds of mussels apparently have been extirpated from these waters. The distribution of many of the surviving species is now quite limited. Domestic and industrial pollution have been ma- jor factors adversely affecting mussel life in the Illinois River. Siltation prob- ably also has affected certain species of mussels, such as the yellow sand-shell (L. a. f. anodontoides) . 7.—At least 38 different kinds of mus- sels are known to have occurred in the upper river (Starved Rock and Mar- seilles navigation pools) in the 1870- 1900 period. By 1912 pollution had vir- tually wiped out the mussels in this sec- tion, and in the 1966 survey no living mussel was taken there. As a result of waste treatment, the dissolved oxygen content of the upper river was much higher in the mid-1960's than it had been in the 1911-1928 period. 8.—By 1930 pollution had affected in varying degrees the mussel life of the entire river. Pollution has had less ef- fect on mussels in the lower part of the river than it has had in the upper por- tion; however, even in the lower river 21 kinds of mussels have been extir- pated in the past 75 years. 9.—The species of mussels found most tolerant to pollution in the Illinois River were the three-ridge [A. plicata), the floater {A. g. corpulenta), the slough sand-shell (L. a. f. fallaciosa) , the ma- ple-leaf {Q. quadrula), the fragile paper shell (L. fragilis), the pink heel-split- ter {P. alata), and the fragile heel-split- ter {P. laevissima) . 10.—The distance and time required for at least partial dissipation of domes- tic and industrial pollutants below the Chicago-Joliet and Peoria-Pekin metro- politan areas were reflected by the ab- sence, presence, and abundance of cer- tain species of mussels. 1 1 .—Experimental deletion-type bio- assay studies with living inussels and/ or other aquatic organisms in river waters and bottom muds might be of value to sanitary and industrial engi- neers. Such studies might isolate the key pollutants limiting mussels and other aquatic life in a stream, thereby greatly reducing costs in the construction and operation of advanced waste treatment plants. 12.—Comparisons between old and new base-line data for mussels revealed that, in spite of the great reduction since 1922 in the biochemical oxygen demand of the wastes discharged into the Illinois waterway, conditions for mussel life have remained poor in most parts of the river. 13.—It was believed that natural se- lection has played an important role in reestablishing the mussel beds in Peoria Lake. Improved treatment of municipal and industrial wastes have also undoubt- edly helped to improve Peoria Lake as a mussel habitat. 14.—The average amount of organo- chlorine pesticides in the mussels analyz- ed from the Illinois River in 1966 was 0.0331 ppm. 15.—Length and height measurements were made of the shells taken alive in the 1966 survey and of some shells in commercial shell piles along the river. Age determinations were made of most of the live mussels taken in the survey. 16.—During the first part of this cen- tury the Illinois River supported a large commercial mussel fishery. The effects of pollution on mussel life and the use of plastics for making buttons virtually 364 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 eliminated this mussel fishing industry. Recently the demand for shells by the Japanese pearl-culture industry has re- juvenated commercial mussel fishing on the Illinois River. 17.—In 1966 a total of 1,118.4 tons of shells were removed from the Illi- nois River commercially. These shells were valued at $109,460.83. All of the 1966 commercial mussel fishing on the Illinois River was done on its lower 87 miles. The locations of the mussel beds fished commercially in 1966 and esti- mates of standing crops of many of these beds are included in this paper. In 1969 commercial mussel fishing was resumed in the vicinity of Peoria where 104.3 tons of shells were removed in that year. 18.—The three-ridge [A. plicata) comprised 74.8 percent of the shells tak- en commercially from the Illinois River in 1966. The second most important commercial shell was the washboard (M. gigantea). 19.—The three-ridge mussel required 10-12 years to attain the minimum com- mercial size of 2.5 inches in height in the Illinois River. The washboard at- tained this height within 7 years. Most of the desirable Quadrula species in this river were too small for commercial use. 20.—The survey data indicated that the mussel beds had recently received heavy fishing pressure in the lower river. Conservation and management recom- mendations for the mussel fishery are suggested in this paper. i LITERATURE CITED Baker, Frank Collins. 1898. The mollusca of the Chicago area. The Pelecypoda. Part I of the natural history survey. Chicago Academy of Sciences Bulletin 3. 130 p. . 1906. A catalogue of the mollusca of Illinois. Illinois State Laboratory of Natural History Bulletin 7(6):53-136. . 1928. The fresh water mollusca of Wisconsin. Part II, Pelecypoda. Wisconsin Geological and Natural History Survey Bul- letin 70. 495 p. (Also University of Wis- consin Bulletin, Serial 1527, General Series 1301) Barrows, Harlan H. 1910. Geography of the middle Illinois valley. Illinois State Geological Survey Bulletin 15. 128 p. Barth, E. F., M. Mulbarger, B. V. Salotto, and M. B. Ettinger. 1966. Removal of ni- trogen by municipal wastewater treatment plants. Water Pollution Control Federation Journal 38(7) : 1208-1219. Bedford. J. W., E. W. Roelofs, and M. J. Zabik. 1968. The freshwater mussel as a biological monitor of pesticide concentrations in a lotic environment. Limnology and Oceanography 13( 1 ): 118-126. Bingham, Rov L. 1968. Reproductive seasons of eight freshwater mussels from the Wabash, White, and East Fork of the White rivers of Indiana. Indiana Department of Natural Resources, Division of Fish and Game, Re- port of subproject 1, survey of the com- mercial mussel fauna of the Wabash and White rivers. Mimeographed. 102 p. Brown, Carl B., J. B. Stall, and E. E. DeTurk. 1947. The causes and efTects of sedimentation in Lake Decatur. Illinois Water Survey Bulletin 37. 62 p. Cahn, a. R. 1949. Pearl culture in Japan. General Headquarters Supreme Commander for the Allied Powers, Natural Resources Section Report 122. 91 p. Calkins, W. W. 1874. The land & fresh water shells of La Salle County, Ills. Ottawa Academy of Natural Sciences Proceedings. 48 p. Call, Richard Ellsworth. 1900. A de- scriptive illustrated catalogue of the mollusca of Indiana. Indiana Department of Geology and Natural Resources 24th Annual Report for 1899:335-536. Clarke. A. H. Jr. 1966. Genetic and eco- phenctypic relationships in northern Ano- donta populations. American Malacological Union Annual Reports for 1966:24-26. , and Clifford O. Berg. 1959. The freshwater mussels of central New York with an illustrated key to the species of northeastern North America. Cornell Uni- versity Agricultural Experiment Station, New York State College of Agriculture Memoir 367. 80 p. Coker, Robert E. 1921. Fresh-water mussels and mussel industries of the United States. U. S. Bureau of Fisheries Bulletin for 1917- 1918, 36:11-89. Cooper, William. 1855. List of shells col- lected by Mr. Schoolcraft, in the Western and Northwestern Territory, p. 515-518. In Henry R. Schoolcraft, Summary narrative of an exploratory expedition to the sources of the Mississippi River, in 1820: resumed and completed, by the discovery of its origin in Itasca Lake, in 1832. Lippincott, Grambo, pnd Co., Philadelphia. Cvancara, Alan M. 1963. Clines in three species of Lampsilis (Pelecypoda: Unioni- dae ) . Malacologia 1 ( 2 ) : 2 1 5-225 . Danglade, Ernest. 1914. The mussel re- sources f)f the Illinois River. U. S. Bureau of Fisheries, appendix 6 to the report of the U. S. Commissioner of Fisheries for 1913. 48 p. Ellis, M. M. 1936. Erosion silt as a factor in aquatic environments. Ecology 17(1) :29- 42. . 1937. Detection and measurement of stream pollution. U. S. Bureau of Fish- eries Bulletin 22:365-437. Forbes, Stephen A., and R. E. Richardson. 1913. Studies on the biology of the upper Illinois River. Illinois State Laboratory of Natural History Bulletin 9( 10) :481-574. , and . 1919. Some recent changes in Illinois River biology. Illinois State Natural History Survey Bulletin 13 (6) : 139-156. , and . 1920. The fishes of Illi- nois. Second ed. Illinois Natural History Survey, cxxxvi + 357 p. Goodrich, Calvin, and Henry van der Schalie. 1944. A revision of the mollusca of Indiana. American Midland Naturalist 32(2):257-326. HosKiNs. J. K., C. C. RrcHHOFT, and L. G. Williams. 1927. A study of the pollution and natural purification of the Illinois River. I. Surveys and laboratory studies. U. S. Public Health Service Bulletin 171. 208 p. Hutchinson, G. Evelyn. 1957. A treatise en limnology. Vol. I. Geography, physics, and chemistry. John Wiley & Sons, Inc., New York. 1,015 p. Illinois Cooperative Crop Reporting Service. 1965. Illinois agricultural statis- tics annual summary. Illinois Department of .Agriculture and U. S. Department of Agri- culture Bulletin 65-1. 109 p. 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The plankton of the Illinois River, 1894- 1899, with introductory notes upon the hydrography of the Illinois River and its basin. Part I. Quantitative investigations and general results. Illinois State Labora- tory of Natural History Bulletin 6(2): 95- 635. LopiNOT, Al C. 1967. The Illinois mussel. Outdoor Illinois 6(3):8-15. Marsh, William A. 1887-1889. Brief notes on the land and fresh-water shells of Mer- cer Co., 111. Conchologists' Exchange 1 (8):42-43, 1 (9&10) :50-51, l(ll):62-63, l(I2):74-75, 2(l):4-5, 2(2):20-21,2(3): 36-37, 2(4):48-50, 2(5) : 65-67, 2(6) :80- 81, 2(7):90-92, 2(8) : 103-104, 2(9) : 110- 111. Nautilus 3(2): 23-24, 3(3): 34-35. Meyer, Edward R. 1968. The distribution and abundance of freshwater mussels of the family Unionidae (Pelecypoda) of the Wabash, White, and East Fork of the White rivers of Indiana. Indiana Depart- ment of Natural Resources, Division of Fish and Game, Report of subproject 2, survey of the commercial mussel fauna of the Wabash and White rivers. Mimeo- graphed. 68 p. Mills, Harlow B., William C. Starrett, and Frank C. Bellrose. 1966. Man's effect on the fish and wildlife of the Illi- nois River. Illinois Natural History Survey Biological Notes 57. 24 p. Ortmann, A. E. 1918. The nayades (fresh- water mussels) of the upper Tennessee drainage. With notes on synonymy and distribution. American Philosophical Soci- ety Proceedings 57:521-626. . 1919. A monograph of the naiades of Pennsylvania. Part III. Systematic ac- count of the genera and species. Memoirs of the Carnegie Museum 8(1): 1-384. . 1920. Correlation of shape and sta- tion in freshwater mussels (Naiades). American Philosophical Society Proceed- ings 59:269-312. Parmalee, Paul W. 1962. Additional faunal records from the Kingston Lake Site, Illi- nois. Illinois State Academy of Science Transactions 55(1):6-12. . 1967. The fresh-water mussels of Illinois. Illinois State Museum, Popular Science Series, Vol. 8. 108 p. PuRDY, W. C. 1930. A study of the pollu- tion and natural purification of the Illinois River. II. The plankton and related or- ganisms. U. S. Public Health Service Bul- letin 198. 212 p. Richardson, Robert E. 1921a. The small bottom and shore fauna of the middle and lower Illinois River and its connecting lakes, Chillicothe to Grafton: its valuation; its sources of food supply; and its relation to the fishery. Illinois State Natural His- tory Survey Bulletin 13( 15) :363-522. . 19216. Changes in the bottom and shore fauna of the middle Illinois River and its connecting lakes since 1913-1915 as a result of the increase, southward, of sewage pollution. Illinois State Natural History Survey Bulletin 14(4):33-75. . 1925a. Changes in the small bottom fauna of Peoria Lake, 1920 to 1922. Illi- nois State Natural History Survey Bulletin 15(5):327-388. . 19256. Illinois River bottom fauna in 1923. Illinois State Natural History Sur- vey Bulletin 15(6) :391-422. . 1928. The bottom fauna of the middle Illinois River, 1913-1925. Its dis- tribution, abundance, valuation, and index value in the study of stream pollution. Il- linois State Natural History Survey Bulletin 17(12) :387-475. Simpson, Charles Torrey. 1914. A descrip- tive catalogue of the naiades, or pearly fresh-water mussels. Bryant Walker, De- troit. 1,540 p. Smith, Hugh M. 1899. The mussel fishery and pearl-button industry of the Mississippi River. U. S. Fish Commission Bulletin for 1898, 18:289-314. Spicer, J. I. 1952. Personal impressions of the Rivers (Prevention of Pollution) Act, 1951. Institute of Sewage Purification Journals: 181-194. /n Louis Klein. 1959. River pollution. I. Chemical analysis, p. 113. Butterworth & Co. (Publishers) Ltd., London. (Original not seen.) Stall, John B. 1966. Man's role in aflfect- ing the sedimentation of streams and res- ervoirs. Second Annual American Water Resources Conference Proceedings: 79—95. , and S. W. Melsted. 1951. The silting of Lake Chautauqua, Havana, Illi- nois. Illinois State Water Survey, in co- operation with Illinois Agricultural Experi- ment Station, Report of Investigation 8. 15 p. Stansbery, David Honor. 1960. The Uni- oninae (Mollusca, Pelecypoda, Naiadacea) of Fishery Bay, South Bass Island, Lake Erie. Ph.D. Thesis. The Ohio State Uni- versity, Columbus. 216 p. . 1961. The naiades (Mollusca, Pele- cypoda, Unionacea) of Fishery Bay, South Bass Island, Lake Erie. Part I. Introduc- tion, history, faunal origins, and physiog- raphy. Sterkiana 5. 37 p. Feb., 1971 Starrett: Mussels of the Illinois River 367 . 1962. The naiades recorded from the Ohio River system of North America (Mol- lusca: Pelecypoda: Unionacea). A check- list compiled from literature and museum records. The Ohio State University and The Ohio State Museum. Mimeographed. 6 p. 1966. Observations on the habitat distribution of the naiad Cumberlandia monodonta (Say, 1829). American Mala- cological Union Annual Reports for 1966: 29-30. (Abstract) 1967. A provisional classification of the Pleurobema cordatum (Rafinesque, 1820) complex in the Mississippi River drainage basin of North America (Mol- lusca: Pelecypoda: Unionacea). Paper presented at the 15th annual meeting of the Midwest Benthological Society at Car- bondale, Illinois. Mimeographed. 2 p. Starrett, William C, and Arnold W. Fritz. 1965. A biological investigation of the fishes of Lake Chautauqua, Illinois. Illinois Natural History Survey Bulletin 29(1): 1-104. Stein, Carol B. 1968. Studies in the life history of the naiad, Amblema plicata (Say, 1817). American Malacological Union An- nual Reports for 1968:46-47. Strode, W. S. 1891a. Mollusks of Thomp- son's Lake, Illinois. Nautilus 4(12): 133- 134. . 18916. Destruction of Anodonta cor- pulenta Cpr. at Thompson's Lake, III. Nau- tilus 5(8):89-90. Sullivan, William T., and Ralph L. Ev- ans. 1968. Major U. S. river reflects sur- factant changes. Environmental Science & Technology 2(3) : 194-200. , and David L. Hullinger. 1969. Phosphates in Peoria Lake. A quantitative and qualitative evaluation of a nutrient in natural waters. Illinois State Academy of Science Transactions 62(2) : 198-217. Tho.mpson, David H. 1928. The "knot- head" carp of the Illinois River. Illinois State Natural History Survey Bulletin 17(8): 285-320. U. S. Geological Survey. 1967. Water re- sources data for Illinois 1966. Part 1: Surface water records. Part 2 : Water quality records. U. S. Department of the Interior, Geological Survey. 249 p. U. S. Public Health Service. 1963. Report on the Illinois River system, water quality conditions: Part 1, Text. U. S. Depart- ment of Health, Education, and Welfare, Public Health Service, Division of Water Supply and Pollution Control, Great Lakes- Illinois River Basins Project. 158 p. Van der Schalie, Henry, and Annette van der Schalie. 1950. The mussels of the Mississippi River. .American Midl'and Naturalist 44(2) :448-466. Verduin. Jacob. 1967. Eutrophication and agriculture in the United States, p. 163- 172. In Nyle C. Brady, Editor, Agriculture and the quality of our environment. Ameri- can Association for the Advancement of Science, Washington, D.C. Vertrees. Herbert H. 1913. Pearls and pearling. Fur News Publishing Co., New York. 203 p. Walker, Ward. [1956.] The story of the metropolitan sanitary district of greater Chicago. The seventh wonder of America. Metropolitan Sanitary District of Greater Chicago. 39 p. Wilson, Charles B., and H. Walton Clark. 1912. The mussel fauna of the Kankakee basin. U. S. Bureau of Fisheries Document 758. 52 p. WuRTz, Charles B. 1962. Zinc eflfects on fresh-water mollusks. Nautilus 76(2): 53- 61. APPENDIX 10 CQ i5 t5O ^ 00^ ^ ;£- i^ i ts t; J3 Z 60 S" », bo ^ a bo g'u: bo §?' S bo a" 2 3 o OO M H « e I, g. boc c i u "^ a 368 Feb., 1971 Starrett: Mussels of the Illinois River 369 i- O <2) O OS i5 •* Cr, o ^ " a « «o tc o ID 2 ^' O — 3 i o o lO — • O 2 lO O—'COCOUSCOlOtDtOCNr^CvI——'0040—'—<040 Q0O4 •^ (Ny^CO—'— • (M CM—- o» O — Or-cOOOOOO—'OOOOOO — — ' — O OO Cl ooocooooocMoaioooooo — o-^o oo o> OOOmoOOO-'*'—'OOCNIOOOOOOOmO —«o 'o OOC-JOicocoOOO—'OOO—'OOOOOOO o— o ooomcooo — — 004000000^000 oo "o oooooooooooo — oooooooo oo oor^m^o—.OCMOO—'Oooooo — ooo o— jh oor^o — eooT}-—.omoooo — ot^o—'O oo !r> OOCMCMt^ — C>IOO — OOOOO — Or^OOO (NO "^ OOiCr-OOcoiOOO — OOOOOOOO—'O lOO ^> ^lOcocor^cocococoocotNOOD^co^r^oo^ oioCMCOa^tO^CDlO CO * CO^CM CM— lO 04 •* O-*'* — iOCMtC—.OOCMOOOOOtCOO—•—rO CMO Cj O—•*c-j'*-*ir)Ti"(NO(N—.omo — — *—'CMO rfO (N CD Ol lO *. O — Oi001'*r~0)OOOOOC0OOO(N-HCMO — o * CM CO CO Ol ^ CM >h OO — OCMCOID-*00 — — ooooooooo oo ''s CM O CN CM t^ ocoocor^co — -^oo—-oocoooo — ooo oo *o CO CO — CJi OCOtO-^—'OOCOO—OCOOOTt'OOOCOCMC'JO — H S Be ^J " ^^04CMWCNlC*IC^CN|C>l(NeOCOCO T^tO^DtO^O—'OOO ^ .C4C^J04(MCM(NCN Ol CO O CM W CM ^ CM CM CO CO CO CO CO oo^—^'^cocoTf'in^ioeocM-— ^ .lO^O^C^ICMCO'^f'^iOOOtD -^CMCMCMCMCMCMCMCMCiCMCM ^hCMCnICMCMCMCMCOCOCOCOCO co-^t£)r^oo(J)00-^CMcoTj«ioin _J^^-J^^(MCMCMCMCMCMCMCM tOOOO-—'CMCOiOiOt^COO^OO-—'CM ^-^CMCMCMCMCMCMCMCMWCMCOCO ^lOt^r^coCTiO-—'C-JcotJ*! Feb., 1971 Starrett: Mussels of the Illinois River 383 Table A-15.—Height frequency distribution of maple-leafs (Quadrula quadrula) taken from the Illinois River by crowfoot bar, dredge, and wading in the 1965 survey. Height 384 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Table A- 17.—Average observed lengths and heights of pimple-backs (Quadrula pustu- losa) of various ages from the 1966 Illinois River collections. Table A- 19.—Average observed lengths and heights of rock pocketbooks (Areidens confragosus) of various ages from the 1966 Illinois River collections. Age Average Average Number in Length Height of Tears in Inches in Inches Mussels Age Average Average Number in Length Height of Tears in Inches in Inches Mussels 4 Feb., 1971 Starrett; Mussels of the Illinois River 385 Table A-21.—Distribution of mussels in the mainstream of the Illinois River since 1870. Kind of Aiussel Upper River' Peoria Pool La Grange Pool Alton Pool Cumberlandia monodonta Fusconaia ebena Fusconaia flava i.flava Fusconaia flava f. undata Megalonaias gigantea Amblema plicata Quadrula quadrula Quadrula pustulosa Quadrula nodulata Quadrula metanevra Tritogonia verrucosa Cyclonaias tuberculata Plethobasus cyphyus Pleurobema coccineum f. solida Pleurobema pyramidatum Elliptic crassidens Elliptio dilatalus Arcidens conjragosus Lasmigona costata Lasmigona complanata Anodonla grandis grandis Anodonla grandis corpulenta Anodonta imbecillis Anodonla suborbiculata Alasmidonta calceolus Alasmidonta marginata Strophitus undulatus Anodontoides ferussacianm Obliquaria refiexa Obovaria olivaria Actinonaias ligamentina Plagiola lineolata Truncilla truncata Truncilla donaciformis Leptodea fragilis Proptera alata Proptera capax Proptera laevissima Carunculina parva Ligumia recta Villosa iris iris LampsiUs anodontoides f. anodontoides Lampsilis anodontoides i. Jallaciosa Lampsilis radiata luteola Lampsilis ventricosa Lampsilis orbiculata f. orbiculata Lampsilis orbiculata f. higginsii Dysnomia triquetra Total Recorded Kinds of Mussels Since 1870 Total Recorded Kinds of Mussels Taken Alive in 1966-1969 A" 386 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Table A-22.—Kinds of mussels taken alive from the mainstream of the Illinois River in the vicinities of Henry and Chillicothe in 1912^ and 1966. Kind of Mussel Henry F. ebena (Ebony Shell) F.f. f. undata (Pig-Toe) M. gigantea (Washboard) A. plicata (Three-Ridge) Q,. quadrula (Maple-Leaf) Q. puslulosa (Pimple-Back) T. verrucosa (Buckhorn) C. tuberculala (Purple Warty-Back) E. crassidcns (Elephant's Ear) E. dilatatus (Lady-Finger) A. confragosus (Rock Pocketbook) L. complanata (White Heel-Splitter) A. g. grandis (Floater) A. g. corpulenla (Floater) A. imbecillis (Paper Pond Shell) S. undulatus (Squaw Foot) O. reflexa (Three-Horned Warty-Back) A- ligamentina (Mucket) P. lineolata (Butterfly) T. truncata (Deer-Toe) L.fragilis (Fragile Paper Shell) P. data (Pink Heel-Splitter) P. laevissima (Fragile Heel-Splitter) C. parva (Liliput Shell) L. a. i. anodontoides (Yellow Sand-Shell) L. a. i.Jallaciosa (Slough Sand-Shell) L. r. luteola (Fat Mucket) L. 0. f. higginsii (Higgin's Eye) pb Feb., 1971 Starrett: Mussels of the Illinois River 387 Table A-23.—Kinds of mussels taken alive from Peoria Lake in 1912, and in the 1924- 1925 and 1966-1969 periods. Kind of Mussel F. ehena (Ebony Shell) F.flava i.flava (Wabash Pig-Toe) F.flava f. undata (Pig-Toe) M. giganiea (Washboard) A. plicata (Three-Ridge) Q.. quadrula (Maple-Leaf) Q. pustulosa (Pimple-Back) Q^ metanevra (Monkey-Face) T. vertucosa (Buckhorn) C. tuberculata (Purple Warty-Back) P. coccineum f. solida E. dilatalus (Lady-Finger) A. conjragosus (Rock Pocketbook) L. complanata (White Heel-Splitter) A. g. grandis (Floater) A. g. coTpulenta (Floater) A. imbecillis (Paper Pond Shell) A. suhorbiculata (Heel-Splitter) S. undulatus (Squaw Foot) O. reflexa (Three-Horned Warty-Back) 0. olivaria (Hickory-Nut) A. ligamentina (Mucket) P. lineolata (Butterfly) T. truncata (Deer-Toe) 7*. donaci/ormis (Fawn's Foot) L.Jragilis (Fragile Paper Shell) P. alala (Pink Heel-Splitter) P. laevissima (Fragile Heel-Splitter) C. parva (Liliput Shell) L. recta (Black Sand-Shell) L. a. f. anodontoides (Yellow Sand-Shell) L. a. {./allaciosa (Slough Sand-Shell) L. r. luteola (Fat Mucket) L. ventricosa (Pocketbook) L. 0. f. higginsii (Higgin's Eye) pb 388 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Table A-24.—Kinds of mussels taken alive from the mainstream of the Illinois River between the Peoria lock and dam and Havana in 1912 and 1966 and from Quiver Lake in 1966." Kind of Mussel Quiver Lake 1966 F. ebena (Ebony Shell) F.f. f. undata (Pig-Toe) M. gigantea (Washboard) A. plicata (Three-Ridge) Q.. quadrula (Maple-Leaf) Q. pustulosa (Pimple-Back) Q_. nodulata (Warty-Back) T. verrucosa (Buckhorn) C tuberculata (Purple Warty-Back) E. dilatatus (Lady-Finger) A. conjragosus (Rock Pocketbook) L. complanata (White Heel-Splitter) A. g. grandis (Floater) A. g. corpulenta (Floater) A. imbecillis (Paper Pond Shell) A. suborbiculata (Heel-Splitter) S. undulatus (Squaw Foot) 0. reflexa (Three-Horned Warty-Back) A. ligamentina (Mucket) P. lineolata (Butterfly) T. truncata (Deer-Toe) T. donacijormis (Fawn's Foot) L.Jragilis (Fragile Paper Shell) P. data (Pink Heel-Splitter) P. capax (Fat Pocketbook) P. laevissima (Fragile Heel-Splitter) L. recta (Black Sand-Shell) L. a. f. anodontoides (Yellow Sand-Shell) L. a. i.fallaciosa (Slough Sand-Shell) L. r. luteola (Fat Mucket) L. ventricosa (Pocketbook) L. 0. f. higginsii (Higgin's Eye) pb Feb., 1971 Starrett: Mussels of the Illinois River 389 Table A-25.—Kinds of mussels taken alive from the mainstream of the Illinois River (including Bath Chute) from below Havana to the La Grange lock and dam in 1912 and 1966." Kind oj Mussel 1912 1966 F. ebena (Ebony Shell) F.f. f. undata (Pig-Toe) M. gigantea (Washboard) A. plicata (Three-Ridge) Q_. quadrula (Maple-Leaf) Q_. pustulosa (Pimple-Back) Q,. nodulata (Warty-Back) Q,. meianevra (Monkey-Face) T. verrucosa (Buckhorn) C. iuberculata (Purple Warty-Back) P. cyphyus (Bullhead) P. coccmeum f. solida E. crassidens (Elephant's Ear) E. dilatatus (Lady-Finger) A. conjragosus (Rock Pocketbook) L. costata (Fluted Shell) L. complanata (White Heel-Splitter) A. g. grandis (Floater) A. g. corpulenta (Floater) A. imbecillis (Paper Pond Shell) A. suborbiculata (Heel-Splitter) 5. undulalus (Squaw Foot) 0. reflexa (Three-Horned Warty-Back) A. ligamentina (Mucket) P. lineolata (Butterfly) T. truncala (Deer-Toe) T. donacijormis (Fawn's Foot) L.Jragiiis (Fragile Paper Shell) P. alala (Pink Heel-Splitter) P. capax (Fat Pocketbook) P. laevissimn (Fragile Heel-Splitter) L. recia (Black Sand-Shell) L. a. f. anodontoides (Yellow Sand-Shell) L. a. l.Jallaciosa (Slough Sand-Shell) L. T. luteola (Fat Mucket) L. ventrieosa (Pocketbook) L. 0. f. higginsii (Higgin's Eye) Danglade (1914:37) and 1966 survey. '' P designates present and A designates absent. ' A single specimen of this species was collected in 1966 at Lake Matanzas, a bottomland lake adjacent to the river below Havana. pb 390 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Table A-26.—Locations of Illinois River mussel beds fished by commercial mussel fish- ermen in 1966." Table A-27.—Estimates of standing crops of mussels in some of the beds fished com- mercially and in two unfished beds in the Illi- nois River in 1 966. River Mile River Bank River Bank 0.3- 2.0 5.0- 5.5 10.3-10.5 13.2-13.5 14.5-14.7 14.9-15.1 19.0-19.5 23.2-23.5 24.2-24.4 27.7-27.9 28.1-29.5 30.5-31.3 33.0-33.5 37.3-37.6 39.1-39.3 40.1^0.8 41.2^2.4 44.0-14.9 45.2-45.4 46.8^7.7 Left Right Right Right Left Right Right Right Left Left Right Right Right Right Right Right Left Right Left Left 48.0-48.9 50.7-51.5 53.0-53.9 54.0-54.7 55.9-56.4 57.8-59.1 60.4-61.5 62.1-62.6 63.8-64.5 65.9-66.5 66.6-66.9 68.9-69.4 72.6-74.3 74.5-75.1 75.2-75.8 79.0-79.9 80.4-80.8 83.5-83.7 86.4-87.0 Right Right Left Right Left Right Right Right Right Left Right Right Right Left Right Right Right Right Left * Based on observations of mussel fishing by the niinois Natural History Survey crew and on inter- views with commercial mussel fishermen. In 1969 commercial mussel fishing was conducted on beds located immediately below Peoria Lake and in Mid- dle and Lower Peoria lakes, as discussed in the text. Shell Weights^ of Commercial Species River River Live in Pounds Per Acre Mile Bank Weights'' oj All Species Height 2.5 in Pounds All Inches Per Acre Sizes or More 1.0 Feb., 1971 Starrett: Mussels of the Illinois River 391 Table A-28.—Number of mussels caught per 5 minutes of fishing with the exploratory crowfoot bar in the 1966 survey of the Illinois River. Kind of Mussel Mussels Caught Per 5 Minutes of Fishing Alton, Alton La Grange Peoria La Grange, and Entire Pool Pool Pool Peoria Pools River" Fusconaia ebena Fusconaiaf. f. undata Megalonaias gigantea Amblema plicata Quadrula quadrula Quadrula pustulosa Quadrula nodulata Arcidens conjragosus Lasmigona complanala Anodonta g. grandis Anodonta g. corpulenta Anodonta irnbeciUis Anodonta suborbiculata Obliquaria reflexa Obovaria olivaria Truncilla truncate Truncilla donacijormis Leptodea fragilis Proptera alata Proptera lanissima Carunculina parva Lampsilis a, (, fallaciosa Lampsilis r. luteola Total 0.1 0.6 392 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 Table A-29.—Number of mussels caught per 5 minutes of fishing with the dredge in the 1966 survey of the Illinois River. Kind of Mussel Mussels Caught Per 5 Minutes of Fishing Alton, Alton La Grange Peoria La Grange, Jind Pool Pool Pool Peoria Pools* Fusconaia ebena Fusconaiaf. f. undata Megalonaias gigantea Amblema plicata Quadrula quadrula Quadrula puslulosa Quadrula nodulata Arcidens confragosus Lasmigona complanata Anodonta g. grandis Anodonta g. corpulenta Anodonta imbecillis Anodonta suborbiculata Obliquaria reflexa Obovaria olivaria Truncilla truncata Truncilla donaciformis Leptodea fragilis Proplera alata Proptera laevissima Carunculina parva LampsHis a. i. fallaciosa Lampsilis r. luteola Total 0.0 Feb., 1971 Starrett: Mussels of the Illinois River 393 Table A-30.—Number of mussels caught per man-hour of fishing by wading in the 1966 survey of the Illinois River. Kind of Mussel Mussels Caught Per Man-Hour of Fishing Alton, Alton La Grange Peoria La Grange, and Entire Pool Pool Pool Peoria Pools River' Fusconaia ebena Fusconaiaf. f. undata Megalonaias gigantea Amblema plicata Quadrula quadrula Quadrula pustulosa Qtcadnda nodulata Arcidens confragosus Lasmigona complanata Anodonta g. grandis Anodonta g. corpulenta Anodonta imbecillis Anodonta suborbiculata Obliquaria reflexa Obovaria olivaria Truncilla truncata Truncilla donaciformis Leptodea fragilis Proptera alata Proptera laevissima Carunculina parva Lampsilis a. i. Jallaciosa Lampsilis r. luteola Total 0.0 INDEX Abundance of mussels in Illinois River {see also under individual species), 288-340 Acknowledgements, 268-269 Actinonaias carinata, 324 ligamentina, 287, 324-325, 340, 349, 350, 351, 355, 357, 385, 386, 387, 388, 389 abundance and/or distribution, 324- 325 host fishes, 325 museum records, 325 old shell records, 325 pollution, 325 Age composition of catch {see individual spe- cies ) Age determinations {see also under individ- ual species), 285 Agricultural pollution {see also pesticides, pollution, and silt), 272-273, 274 Alabama River, 291 Alasmidonta calceolus, 287, 320-321, 340, 385 abundance and/or distribution, 321 museum records, 321 pollution, 321 {Decurambis) marginata, 321 marginata, 287, 321, 340, 385 abundance and/or distribution, 321 museum records, 321 pollution, 321 viridis, 320-321 Alasmodonta complanata, 314 confragosa, 312 Algae, 275, 342, 347 Alkalinity, 370-373 Alligator gar, 334 Alton navigation pool, 271, 272, 273, 274, 280, 289, 293, 295, 296, 298, 301, 303, 304, 305, 312, 314, 323, 327, 328, 330, 336, 345. 346, 354, 355-357, 359, 361, 368, 370, 374, 376, 379, 381, 382, 385 Amblema, 267 {Amblema) plicata costata, 297 {Amblema) plicata plicata, 297 costata, 297, 298 {Megalonaias) gigantea gigantea. 295 peruviana, 297 plicata. 287, 297-300, 343, 349, 350, 351, 352, 353, 355, 357, 358, 360, 361, 362, 363, 364, 374, 375, 385. 386, 387, 388, 389 abundance and/or distribution, 298 age and/or size, 298, 360, 380-381 commercial, 298, 360 crowfoot bar, 380, 391 dredge, 380, 392 live mussel records, 299-300 museum records, 299 old shell records, 300 pollution, 298-299, 358 rank, 293, 294 standing crop, 298, 360 wading, 380, 393 plicata forma costata, 298 plicata forma plicata, 297, 298 plicata forma rariplicata, 297 rariplicata, 297, 351 Ammonia nitrogen, 269, 274, 344-345, 349, 350, 353, 355 Ammoniacal nitrogen, 345 Ancillary air diving devices, 362 Anodonta {Anodonta) grandis grandis, 315 {Anodonta) imbecilis, 319 cataracta, 315 corpulenta, 315, 316, 317, 318 gigantea, 315, 316 grandis, 314, 317, 318 grandis complex, 314-319, 357, 361 museum records, 318 taxonomy, 314-318 grandis grandis, 287, 317, 318-319, 350, 352, 374, 375, 385, 386, 387, 388, 389 abundance and/or distribution, 318 crowfoot bar, 391 dredge, 392 host fishes, 318 live mussel records, 318-319 museum records, 318 rank, 293-294 wading, 393 grandis corpulenta. 287, 317, 318, 319, 349, 350, 352, 358, 363, 374, 375, 385, 386, 387, 388, 389 abundance and/or distribution, 319 crowfoot bar, 391 dredge, 392 host fish, 319 live mussel records, 319 museum records, 319 old shell records, 319 pollution, 319, 358 rank. 293-294, 319 wading, 393 grandis var. gigantea. 315, 316, 318 imbecilis, 319 imbecillis. 287, 319-320, 350, 351, 352. 356, 357, 374, 375, 385, 386, 387. 388, 389 abundance and/or distribution, 319- 320 crowfoot bar, 391 dredge, 320. 392 host fish, 320 live mussel records, 320 museum records, 320 pollution. 320 rank, 293-294 394 Feb., 1971 Starrett: Mussels of the Illinois Ri\'er 395 wading, 320, 393 imbicilUs, 319 ovata. 315, 318 (Pyganodon) coTpulenta, 315 (Pyganodon) grandis, 315 suborbiculata. 287, 320, 340, 342, 352, 385, 387, 388, 389 abundance and/or distribution, 320 crowfoot bar, 391 dredge, 392 live mussel records, 320 museum records, 320 rank, 293-294 wading, 393 (Utterbackiana) suborbiculata, 320 Anodontinae, 312-322 Anodontoides jerussacianus, 287, 322. 340, 385 abundance and/or distribution, 322 museum records, 322 Arcidens confragosa. 312 confragosus. 287, 312-313, 350, 352, 357, 361, 374, 375. 385, 386, 387, 388, 389 abundance and/or distribution, 312 age and/or size, 312, 384 crowfoot bar, 391 dredge, 392 live mussel records, 312-313 museum records, 312 old shell records. 313 pollution, 312 rank, 293-294, 312 wading, 393 Arkansas, 291, 329 Atlantic Coast, 315 Aux Sable River, 276, 277, 291-292, 322, 346 B Bacteria and bacteriology, 274, 275, 343, 369 Baker, Frank C. collections, 286 Bank, river, 271 Banner, 294, 299, 309, 311 Base-line data, 268, 363 Basket dredges, 362 Bath, 304. 306, 307, 310, 313, 319, 320, 321, 326, 340, 359 Bath Chute, 296, 374, 376, 389 Bathers (see swimming) Beardstown, 294, 296, 299, 301, 331, 335, 336, 340, 351, 354, 359 Bedford, 304, 320, 324, 325, 328 Beds {see mussels) Bioassay, 345, 363 Biochemical oxygen demand (BOD). 274. 343. 345. 353. 363. 368 Black bullhead, 345 Black crappie. 293. 299. 304, 334, 346 Black River, 291 Black Sand-Shell {see Ligumia recta) Bluegill, 299, 304, 305, 318, 325, 336, 346 Blue-Point {see Amblema plicata) Boaters, 343 Bones {see old shell records) Bottom fauna, 351, 354 Bottomland lakes, 270-271, 286, 342, 363 Bowfin {see dogfish) Browning. 304, 307, 339, 359 Buckhorn {see Tritogonia verrucosa) Buckhom Landing, 334 Bullhead {see Plethobasus cyphyus) Butterfly {see Plagiola lineolata) Button industry, 267, 289, 295, 302, 304, 306. 307, 308, 310, 325, 363-364 Calhoun County, 324, 328, 329, 332 Canada. 315 Carchesium, 343 Carp. 318, 345, 346 Carp-goldfish hybrids, 345, 346 Carunculina parva, 287, 331-332, 342, 356, 357, 374, 375, 385, 386, 387 abundance and/or distribution, crowfoot bar, 391 dredge. 392 live mussel records, 332 museum records. 331-332 old shell records, 332 rank, 293-294 wading, 331, 393 Catfishes, 299 Centrarchidae, 278. 346 Channel catfish. 303, 346 Charts of the Illinois Waterway, 271 Chemistry, water, 273-275, 368-373 Chicago. 269. 273, 307, 342, 343, 344, 347, 348, 353, 354, 362 Chicago-Joliet metropolitan area, 363 Chicago Sanitary and Ship Canal, 321, 342, 343, 348, 362 Chillicothe. 289, 292, 293, 294, 304. 305, 306. 307, 310, 323, 349, 350-351 352. 331 344, 269. 295, 327, 346. 345, 313. 296, 332. 346,339, 340, China, 268 Chlorides, 368 Chromium, 274 Clear Lake, 328 Clinch River, 311 Cline, 291, 337 Collecting methods, 276-284, 376-377 Commercial mussel fishing, 267, 289, 351 356. 358-362, 363-364 Commercial shell pile(s), 284, 293, 295: 363 Commercial shell yield (s), 267, 268, 353, 364 Conservation, 358-362 Cook County. 334 Copper, 274 Copperas Creek, 271 Cowan Creek, 317 Cowan Lake, 317 Creek chub, 322 Crenodonta peruviana, 297 Crowfoot bar (brail) 352. 361, 352- 364 276, 278-281, 284. 396 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 342-343, 344, 350, 351, 353, 362, 376- 377, 378, 380, 383, 391 Cumberland River, 290, 291, 300 Cumberlandia monodonta, 287, 288, 340, 385 abundance and/or distribution, 288 museum records, 288 Current, 271-272, 351 Cyclonaias tuberculata, 287, 306-307, 340, 357, 385, 386, 387, 388, 389 abundance and/or distribution, 306 museum records, 307 old shell records, 307 tuberculata compressa, 306 tuberculata granifera, 306, 307 Cylindrical Paper Shell {see Anodontoides ferussacianus) Dam(s), 271, 274, 307, 324, 330, 343, 350 Dark Chute, 326 Deer-Toe {see Truncilla truncata) Des Plaines River, 269, 270, 274, 313, 334, 342, 343. 347, 362 Detergents, 274-275, 370-373, 385 Diameter {see height) Diamond Island, 288, 306, 310, 326 Dip net {see dredge) Discharge, 270 Distribution of mussels in Illinois River {see also under individual species), 288-340, 341, 374, 375, 385 Diversion of water, 269, 342 Dogfish, 296 Domestic pollution {see also pollution and population, equivalent), 274 Dredge, 276, 280, 281-284, 320, 350, 352, 360, 362, 376-377, 378, 380, 383, 392 Dresden navigation pool, 271, 273, 342, 373 Drum, freshwater, 326, 327, 330, 346 Dysnomia triquetra, 287, 340, 385 abundance and/or distribution, 340 museum records, 340 Ebony Shell {see Fusconaia ebena) Ecosystem, 278, 362 Efficiency of mussel fishing devices, 362 Electrofishing, 275, 278, 346 Elephant's Ear {see Elliptio crassidens) Elk-Toe {see Alasmidonta marginata) Ellipsaria lineolata, 325 Elliptio crassidens, 287, 309-310, 340, 357, 385, 386, 389 abundance and/or distribution, 310 museum records, 310 old shell records, 310 dilatatus, 287, 310-311, 340, 350, 351, 352, 355, 357, 385, 386, 387, 388, 389 abundance and/or distribution, 310- 311 museum records, 311 old shell records, 311 pollution, 311 {Eurynia) dilatatus dilatatus, 310 Emerald shiner, 345 Engineers, 345, 349, 363 Exotic fish species, 345 Exploratory mussel fishing, 280 Extirpated species of mussels, {see also in- dividual species), 340, 347, 351, 355, 362 Fairport, 324 Fat Mucket {see Lampsilis radiata luteola) Fat Pocketbook {see Proptera capax) Fawn's Foot {see Truncilla donaciformis) Fertilizers, agricultural, 345 Field Museum of Natural History {see also under individual species), 285, 286, 292, 298, 301, 309 Field procedure, 276-284 Fish(es) {see also host fishes and individual species of fishes and mussels), 275-276, 345 Flathead catfish, 296 Floater {see Anodonta grandis complex) Florence, 292, 299, 310, 321. 324, 338, 340 Fluted Shell {see Lasmigona costata) Forks, hand (scissor), 281, 362 Fox River, 292, 313, 330, 333, 337 Fragile Heel-Splitter {see Proptera laevissima) Fragile Paper Shell {see Leptodea fragilis) Frederick, 296, 299, 312, 335 Fulton County, 326, 340 Fusconaia antrosa, 289 ebena, 287, 288-289, 290, 342. 349, 351, 356, 357, 374. 375. 385, 386. 387, 388, 389 abundance and/or distribution, 289 age and/or size, 289 commercial, 289 crowfoot bar, 289, 391 dredge, 392 host fish, 289 live mussel records, 289 museum records, 289 old shell records, 289 pollution, 289 rank, 293-294 siltation, 289 wading, 393 ebenus, 288 flava, 291 flava complex, 290-291 flava forma flava, 287, 291-292, 340, 385, 387 flava forma parvula, 290 flava forma rubignosa, 290 flava forma trigona, 291, 292 flava forma trigonus, 290 flava forma undata, 287, 291, 292-295, 350, 351, 352, 357, 361. 374. 375. 385, 386, 387, 388, 389 abundance and/or distribution, 292- 294 Feb., 1971 Starrett: Mussels of the Illinois Rfver 397 age and/or size, 293, 378 commercial, 293 crowfoot bar. 391 dredge, 392 host fishes, 293-294 live mussel records, 294—295 museum records, 294 old shell records, 295 pollution, 294 rank, 293-294 wading. 393 flava forma undatus, 290 flava -forma wagneri, 290 subrotunda, 287, 289-290 undata, 292 undata undata, 292 undata wagneri, 292 Gars, 299 Gastropoda, 347 Gizzard shad, 296 Glochidium (ia), 275. 293. 299, 315-316, 317, 346 Goldfish, 345, 346 Grafton. 267, 270, 277. 296, 299, 301, 303, 304, 305, 310, 312, 323, 324, 325, 326, 327, 328, 329, 330, 335, 336, 337, 354, 362, 369, 370, 374 Grand Island, 305, 311, 326 Greater Peoria Sanitary District, 274, 353 Green River, 31 1 Green sunfish, 299. 325, 334, 346 Gulf Coast, 315 H Hand picking {see wading) Hardin, 288, 289, 292, 294, 296, 299, 303, 304, 306, 311, 312, 321, 322, 323 324, 325, 326, 327, 328, 329, 331, 332, 334, 335, 337. 338, 339, 340 Hardness, 368 Havana, 270, 271, 272, 295, 296, 299, 301, 306, 307. 309. 310, 319, 320, 322, 323, 328, 329, 331, 332, 334, 335, 336, 337. 338, 339, 340, 354, 355 Havana-La Grange dam section, 355, 389 Heel-Splitter {see Anodonta suborbiculata) Height, {see also individual species), 284— 285, 290, 363 Height index, 290, 316, 317 Hennepin, 270. 293. 301. 305, 312, 314, 318, 320, 322, 331, 336, 337, 347. 350 Hennepin-Chillicothe section, 330. 348 Henry, 289, 295, 296, 299, 303, 304, 305. 310, 312. 325. 326. 327, 328, 329, 330, 335, 336, 348, 350 Henry-Chillicothe section, 289, 323, 325, 326, 331, 334, 337, 348-349, 386 Hickory-Nut {see Obovaria olivaria) Higgin's Eye {see Lampsilis orbiculata forma higginsii) 288, 398 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 old shell records, 334 pollution. 334. 356 siltation, 334 anodontoides forma fallaciosa, 284, 287, 333, 334-336, 349. 350. 351, 352, 357. 361, 363, 374, 375, 385, 386, 387, 388, 389 abundance and/or distribution, 335 age and/or size, 335 commercial, 335 crowfoot bar, 335, 350, 391 dredge, 335, 350, 392 host fishes, 335 live mussel records, 335-336 museum records, 335 old shell records, 336 pollution, 335, 363 rank, 293-294. 335 wading. 335. 350. 392 capax, 330 cardium, 337 ellipsis, 323 fallaciosa, 334 gracilis, 327 higginsi(i), 338, 339 higginsii var. grandis, 339 laevissima, 330, 343 laevissimus, 330 (Lampsilis) cardium, 337 (Leptodea) fragilis, 327 leptodon, 328 ligamentina, 324 ligamentinus, 324 (Ligumia) siliquoidea siliquoidea, 336 (Ligumia) teres fallaciosa, 335 (Ligumia) teres teres, 333 luteola, 336 luteolus, 336 occidens, 337 orbiculata, 338 orbiculata complex, 338-340 museum records, 338 old shell records, 338 orbiculata forma higginsii, 287, 338, 339- 340, 357, 386, 387, 388, 389 abundance and/or distribution, 339- 340 host fishes, 340 museum records, 340 old shell records, 340 pollution, 340 siltation. 340 orbiculata forma orbiculata, 287. 338- 339, 340, 385 abundance and/or distribution, 339 museum records, 339 ovata complex, 337 ovata forma ventricosa, 337 parva, 331 parvus, 331 radiata luteola, 287, 336-337, 351, 352, 357. 374. 375, 385, 386, 387, 388, 389 abundance and/or distribution, 336 age and/or size, 336 crowfoot bar, 391 dredge, 392 host fishes, 336-337 live mussel records, 337 museum records, 337 old shell records, 337 rank, 293-294, 336 wading, 393 radiata siliquoidea, 336 recta, 332 rectus, 332 siliquoidea, 336 subrostrata, 332 teres, 333, 334 ventricosa, 287, 337-338, 340, 343, 349. 357, 385, 387, 388, 389 abundance and/or distribution, 337 host fishes, 337-338 museum records, 338 old shell records, 338 pollution, 337 siltation, 337 ventricosus, 337 Largemouth bass, 304, 325, 334, 346 La Salle, 270, 301, 303, 305, 326, 327, 328. 335, 337, 347, 354 La Salle County, 289, 304, 307, 308, 310, 314, 318, 320, 323, 326, 328, 330, 332, 333, 334, 335, 336, 338, 339, 340 La Salle-Peru area, 321, 325, 328, 329, 349- 350 Lasmigonct complanata, 287, 314, 343, 349, 350, 352, 357, 361, 374, 375, 385, 386, 387, 388, 389 abundance and/or distribution, 314 commercial, 314 crowfoot bar. 391 dredge. 392 live mussel records. 314 museum records. 314 old shell records, 314 pollution, 314 rank, 293-294, 314 wading, 393 compressa, 287, 313-314 costata, 287, 313, 340, 385 abundance and/or distribution, 313 pollution, 313 Lastena lata, 287. 311-312 Laws regulating mussel fishing, 360-362 Length, 284, 316, 363 Lepomis sp., 320 Leptodea fragilis, 285, 287, 327-328, 349, 350, 352, 357, 358, 363, 374, 375, 385, 386, 387, 388, 389 abundance and/or distribution, 328 age and/or size, 328 crowfoot bar, 391 dredge, 392 live mussel records, 328 museum records, 328 Feb., 1971 Starrett: Mussels of the Illinois Rwer 399 old shell records, 328 pollution, 328, 358 rank, 293-294, 328 wading, 393 laevissima, 330 leptodon, 287, 328-329 License sales, 268 Ligumia iris novieboraci, 333 latissima, 332 recta, 287, 332, 340, 357, 385, 387, 388, 389 abundance and/or distribution, 332 museum records, 332 old shell records, 332 pollution, 332 recta latissima, 332 subrostrala, 287, 332 Liliput Shell (see Carunculina parva) Liverpool, 299, 312, 314, 318, 328, 335, 355 Longnose gar, 334 M Management, 358-362, 364 Maple-Leaf (see Quadrula quadrula) Margaritana complanata, 314 confragosa, 312 deltoidea, 320 margaritifera, 288 marginata, 321 monodonta, 288 rugosa, 313 Margaritifera margaritifera, 287, 288 Margaritiferidae, 288 Marseilles navigation pool, 271, 272, 273, 274, 276, 280, 294, 295, 303, 307, 342, 346, 363, 368, 373, 375, 377 Measurements, shell, 284-285 Megalonaias, 267 gigantea, 287, 295-297, 350, 351, 352, 355, 356, 357, 358, 360-361, 362, 363, 364, 374, 375, 385, 386, 387, 388, 389 abundance and/or distribution, 295 age and/or size, 295, 378, 379 commercial, 295 crowfoot bar, 295, 296, 378, 391 dredge, 378, 392 host fish, 296 live mussel records, 296-297 museum records, 296 old shell records, 297 pollution, 295-296, 358 rank, 293-294, 295 standing crop, 296 wading, 295, 378, 393 Mercer County, 316 Meredosia, 284, 289, 294, 296, 299, 301, 303, 304, 305, 306, 307, 309, 310-311, 312, 314, 318, 320, 323, 324, 325, 326, 327, 328, 329, 331, 334, 335. 336, 337, 338, 340, 356, 36! Meredosia Lake, 271, 277, 303, 319, 327, 374, 376 Metals (see also various kinds of metals), 274, 345 Middens, 309-310, 321 Mile, river, 271 Minnows, 299 Mississippi River, 267, 268, 270, 288, 290, 304, 306, 307, 310, 315, 317, 324, 339, 362 Missouri, 329 Monkey-Face (see Quadrula metanevra) Montezuma, 299 Morris, 304, 307, 321, 327, 342, 343 Mossville, 320, 335 Mucket (see Actinonaias ligamentina) Museum records (see also under individual species), 285-286 Museum of Comparative Zoology (see also under individual species), 286, 292, 322, 335 Mussel (s) (see also under individual species), ammonia nitrogen, 344—345, 349, 350, 353, 355 beds, 276, 277, 278, 352-353, 354-355, 355-356. 359, 364, 390 changes in fauna, 286-340 fauna of Illinois River, 286-340 kinds in Alton pool, 345, 355-357, 374, 385 kinds in Illinois River, 287, 341, 374- 375, 385 kinds in La Grange pool, 345, 353-355, 374, 385 kinds in Peoria pool, 346-353, 385 kinds in upper river, 342-346 oxygen, dissolved, 343-344. 351-352, 354, 355 Mussel fauna (see mussels) Mussel fishermen, 267, 289. 351, 352, 356, 358-362, 363-364 N Naiads (see mussels) Naples, 289, 294, 296. 299. 301, 303, 304, 305. 306. 307. 309, 311, 312, 314, 318, 323, 326, 327. 328, 329, 331, 334, 336, 337, 356 Natural selection, 353, 363 Navigation channel, 271 Navigation pools (see also under individual pools), 271 Nets, 346 New England, 322 New York, 322 Nickel, 274 Nitrates, 368 Nitrification oxidation. 274 Obliquana reflexa, 287, 322-323. 349, 352, 356. 357, 374. 375, 385. 386, 387, 388, 389 400 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 abundance and/or distribution. 322- 323 age and/or size, 323, 384 commercial, 323 crowfoot bar, 391 dredge. 392 live mussel records. 323 old shell records. 323 museum records, 323 pollution. 323 rank. 293-294 wading. 323, 393 Obovaria ellipsis, 323 olivaria, 287, 323-324, 342. 374. 375, 385, 387 abundance and/or distribution, 323- 324 age and/or size, 323 crowfoot bar, 323, 391 dredge, 392 live mussel records, 324 museum records, 324 pollution, 324 rank, 293-294 wading, 393 retusa. 287, 324 Odor, 343 Ohio River. 290. 298. 300, 306, 308, 311, 324, 339 Ohio State Museum {see also under individ- ual species), 285, 286, 290, 299, 309 Oklahoma, 329 Old shell records {see also under individual species), 284, 285, 286, 288, 363 Orangespotted sunfish, 334, 346 Organochlorine pesticides {see pesticides) Organophosphate pesticides {see pesticides) Ottawa, 295, 301. 318, 319, 330. 337, 342 Overfishing. 267. 360 Oxygen, dissolved. 274. 343-344, 345. 348, 349. 350, 351-352, 354. 355. 363, 370-373 Paper Pond Shell {see Anodonta imbecillis) Pearl(s), 267, 276 Pearl culture, 267, 268, 295, 302, 304, 323, 360. 361, 364 Pearl, Illinois. 294. 296, 299, 301, 303, 304, 310, 312, 314. 324 Pekin, 270, 292, 294, 299, 321, 328, 330, 354, 355 Pekin-Havana section, 296, 299, 303, 305, 318, 325, 328, 335, 338 Peoria, 267, 294, 296, 298, 299, 301, 303, 305, 306, 310, 321. 323, 324, 325, 326, 327, 331, 332, 335, 339. 340, 347, 364 Peoria dam-Havana section, 354-355, 388 Peoria Lake, 272, 274, 281, 289, 292, 293, 295. 300. 301. 303. 304. 305, 308, 310, 311, 312, 314, 318, 319. 320, 321, 322, 323, 324, 325, 327, 328, 330, 331, 335, 336, 337, 340, 344, 346, 347, 348, 351- 353. 356. 359. 363. 387, 390 Peoria Lake-Peoria dam section, 353 Peoria Narrows, 272, 296, 301, 311, 323, 329, 330, 335, 347, 351 Peoria-Pekin metropolitan area, 274, 344, 345. 353-354, 363 Peoria-Pekin section, 296, 299, 312, 318, 328, 329, 330, 353-354 Peoria navigation pool, 271, 272, 273, 274, 276, 280, 286, 293, 298, 301, 303, 312, 318, 319, 343, 345, 346-353, 360, 362, 368, 372, 375, 377, 381, 382, 385 Peru, 267, 292, 294, 299, 301, 303, 305, 312, 320, 322, 325, 326, 328, 329, 331, 332, 335. 337, 338, 347, 349 Pesticides organochlorine, 269, 276, 357-358, 363 organophosphate, 358 Phelps Lake, 311 Phosphates, total, 269, 275, 345, 349, 353 Phosphorus, 275 Pig-Toe {see Fusconaia flava forma undata) Pimple-Back {see Quadruta pustulosa) Pinctada, 267 Pink Heel-Splitter {see Proptera alata) Pistol-Grip {see Tritogonia verrucosa) Plagiola donaciformis, 327 elegans, 326 lineolata, 287, 325-326, 340, 357, 385, 386, 387, 388, 389 abundance and/or distribution, 325- 326 host fish, 326 museum records, 326 old shell records, 326 pollution, 325-326 securis, 325 Plagiolopsis lineolata, 325 Plankton, 347, 354 Plethobasus cyphyus, 287, 307-308, 340, 357, 385, 389 abundance and/or distribution, 307 host fish, 307 museum records, 307 old shell records, 308 pollution, 307 Pleurobema, 267 aesopus, 307 catillus var. coccinea, 308 catillus var. solida, 308, 385 coccineum coccineum, 308 coccineum forma solida, 287, 309, 340, 357. 387, 389 museum records, 309 old shell records, 309 coccineum solida, 308 cordatum, 308 cordatum complex, 308-309 abundance and/or distribution, 308- 309 commercial, 308 museum records, 309 {cordatum) pyramidatum, 308 plenum, 308 Feb., 1971 Starrett: Mussels of the Illinois River 401 pyramidatum, 287, 309, 340, 385 museum records, 309 Pocketbook (see Lampsilis ventricosa) Pollution, 273-275, 340-358 agricultural, 272-273, 274, 342, 345, 346, 354, 355, 357-358 domestic (sewage), 274, 342, 358, 362, 363 effects on fish and wildlife, 267, 343, 345 effects on mussels (see also under in- dividual species), 267, 340-358, 363 industrial, 274, 342, 345, 354, 358, 362, 363 Pollution-tolerant mussels, 298-299, 301, 319, 328, 329, 330, 335, 343, 352, 355, 363 Pond-Horn (see Uniomerus tetralasmus) Pond Mussel (see Ligumia subrostrata) Population, equivalent, 274, 348-349, 353, 354 Population, human, 273, 348 Potamilus alata megapterus- 329 alata megapterus, 329 alatus, 329 capax, 330 ohiensis, 330 Proptera alata. 285, 287, 329-330, 349, 350, 352, 357, 358, 363, 374, 375, 386, 387, 388, 389 abundance and/or distribution, 329 age and/or size, 329 commercial, 329 crowfoot bar, 391 dredge, 392 live mussel records, 329—330 museum records, 329 old shell records, 330 pollution, 329. 358 rank, 293-294, 329 wading, 393 capax. 287, 330, 340, 385, 388, 389 abundance and/or distribution, 330 museum records, 330 laevissima, 287, 330-331, 350, 352, 357, 363, 374, 375, 385, 386, 387, 388, 389 abundance and/or distribution, 330 age and/or size, 330 crowfoot bar, 391 dredge, 392 host fishes, 330-331 live mussel records, 331 museum records, 331 old shell records, 331 pollution, 330 rank, 293-294 wading, 393 Pumpkinseed, 299, 346 Purple Warty-Back (see Cyclonaias tuber- culata) Quadrula, 267, 349, 364 asperrima, 300 bullata. 302 coccinea, 308 ebena, 289 fragosa, 300 granijera, 306 heros. 295 lachrymosa, 300 metanevra. 287, 304-305, 340, 357, 385, 387, 389 abundance and/or distribution, 304- 305 host fishes, 305 museum records, 305 old shell records, 305 pollution, 305 metanevra wardii, 304 multiplicata, 295 nodulata. 287, 303-304, 355, 356, 357, 374, 375, 385, 388, 389 abundance and/or distribution, 303- 304 age and/or size. 304, 384 crowfoot bar, 391 dredge, 392 host fish, 304 live mussel records, 304 museum records, 304 old shell records, 304 pollution, 304 rank, 293-294, 303-304 wading, 393 obliqua. 308 (Obliquata) catillus, 308 (Obliquata) coccinea coccinea, 308 (Obliquata) obliquata, 308 (Orthonymus) metanevra, 304 plena, 308 plicata, 297 pustulata, 303 pustulosa, 287, 302-303, 304, 349, 350, 351, 352, 353, 355, 356, 357, 358, 361, 362, 363, 374, 375, 385, 386, 387, 388, 389 abundance and/or distribution, 302 age and/or size, 302, 383-384 crowfoot bar, 383, 391 dredge, 383, 392 host fish, 303 live mussel records, 303 museum records, 303 old shell records, 303 pollution, 303, 358 rank, 293-294, 302 standing crop, 302 wading, 383, 393 (Pustulosa) nodulata, 303 (Pustulosa) pustulosa pustulosa, 302 pyramidata, 308 quadrula, 287, 300-302, 350, 352, 355, 357, 358, 361, 362, 363, 374, 375, 385, 386, 387, 388, 389 402 Illinois Natural History Survey Bulletin Vol. 30, Art. 5 abundance and/or distribution, 300 301 age and/or size, 300-301, 382, 383 crowfoot bar, 383, 391 dredge, 383, 392 host fishes, 301 live mussel records, 301-302 museum records, 301 old shell records, 302 pollution, 301, 358 rank, 293-294, 300 standing crop, 301 wading, 383, 393 (Quadrula) quadrula quadrula, 300 rubiginosa, 291 solida, 308 subrotunda, 289 trigona, 292 tuberculata, 306 undata, 292 undulata, 297 Quantitative samples, 284 Quiver Lake, 271, 277, 294, 295, 296, 301, 302, 303, 312. 313, 314, 318, 319, 320, 323, 327, 328, 330, 331. 335, 336, 337, 355, 374, 376, 388 Radiological determinations, 274, 369 Rainbow-Shell {see Villosa iris iris) Rakes, hand, 281, 362 River bank, 271 River mile, 271 Rock bass, 299, 318, 346 Rock Pocketbook {see Arcidens conjragosus) Rock River, 313 Rotundaria tuberculata, 306, 307 Row crops, 272 Sabine River, 291 St. Francis River, 291 Sampling method, 276-278 Sanger, 305, 307, 338, 340 Selectivity of mussel fishing devices, 362 Seventy-fifth General Assembly of Illinois, 362 Sewage {see pollution) Sheepnose {see Plethobasus cyphyus) Shortnose gar, 334, 335 Shovelnose sturgeon, 335 Silt {see also under pollution), 267, 272-273, 311, 324, 325, 326, 333, 334, 337, 340, 346, 354, 355, 356, 363 Sintoxia antrosa, 289, 324 lateralis, 291, 292 Six-Mile Island, 328 Skipjack herring, 289, 319 Slipper-Shell {see Alasmidonta calceolus) Slough Sand-Shell {see Lampsilis anodontoides forma fallaciosa) Sludge, 343 Slugs, {see pearls) Smallmouth bass, 325, 346 Snails {see Gastropoda) Snuffbox {see Dysnomia triquetra) Soils, bottom, 272-273, 280, 320, 345, 381 Solids, total, 368 Spar Island, 325 Spectacle-Case (see Cumberlandia monodon- ta) Sphaerotilus, 343, 348 Spike {see Elliptio dilatatus) Spoon River, 292, 300, 311 Spring Valley, 294, 295, 301, 303, 312, 318, 335, 347 Spring Bay Narrows, 311, 351 Squaw Foot {see Strophitus undulatus) Standing crop(s) {see also under individual species), 285, 353, 359-360. 362, 364, 390 Starved Rock, 273, 274, 296, 299, 309, 312, 313, 314, 324, 326, 327, 333, 335, 338. 342, 343, 345, 348, 350, 385 Starved Rock dam-Chillicothe section, 347- 349 Starved Rock navigation pool, 271, 272. 280, 289, 292, 293, 294, 301, 303, 304. 305, 307, 308, 310, 312, 313. 314. 320. 323, 324, 328, 330, 332, 335, 336. 339, 342. 346. 363, 368, 373, 375, 377 Strophitus edentulus, 321 rugosus, 321 undulatus, 287, 321-322, 340, 349, 350. 385, 386, 387, 388, 389 abundance and/or distribution. 321 host fishes. 322 museum records, 322 Sulfate, 368 Summary, 362-364 JL Sunfishes, 278, 346 Swimming, 343 Symphynota complanata, 314 compressa, 313 costata, 313 Temperature, 370-373 Tennessee River, 267, 290. 291, 317 Tennessee Shell Company, 278-279, 283 Terre Haute, 306 Texas, 291 Thompson Lake, 270, 318, 320. 331 Three-Horned Warty-Back {see Obliquaria reflexa ) Three-Ridge {see Amblema plicata) Tolerant species {see pollution-tolerant mus- sels) Tongs, oyster, 281 Towboat, 273, 354 Toxolasma parva, 331 parvum parvum, 331 Transverse index. 290 Tritogonia tuberculata, 305 verrucosa, 287. 305-306, 350, 356, 357, 374, 385, 386, 387, 388. 389 abundance and/or distribution, 305 live mussel records, 306 Feb., 1971 Starrett: Mussels of the Illinois River 403 museum records, 305-306 old shell records, 306 pollution. 305 verrucosa verrucosa, 305 Truncilla (Amygdalonaias) donaciformis, 327 donaciformis, 287, 327, 342, 356, 357, 374, 375, 385, 387, 388, 389 abundance and/or distribution, 327 crowfoot bar, 327, 391 dredge, 327, 392 host fishes, 327 live mussel records, 327 museum records, 327 old shell records, 327 pollution, 327 rank, 293-294 wading, 327, 393 triquetra, 340 truncata. 287, 326-327, 350, 355, 357, 374, 375, 385, 386, 387, 388, 389 abundance and/or distribution, 326 age and/or size, 326 crowfoot bar, 391 dredge, 392 live mussel records, 326—327 museum records, 326 old shell records, 327 pollution, 326 rank, 293-294, 326 wading, 393 vermiculata, 326 Turbidity, 272-273 Twelve-Mile Island. 310, 324, 340 u Unto Aesopus, 307 anodontoides, 333, 334 capax, 330 coccineus, 308 cornutus, 322 crassidens, 309 ebenus, 289 elegans, 326 ellipsis, 323 gibbosus, 310 gracilis, 327 iris, 333 ligamentinus, 324 luteolus, 336 metanevrus, 304 obliquus, 308 orbiculatus, 339 parvus, 331 peruviana, 297 plicata, 298 pustulatus, 303 pustulosus, 302 rariplicata, 298 rectus, 332 retusus, 324 rubiginosus. 291, 292 solidus, 308 tetralasmus, 311 triangularis, 340 trigonus, 292 tuberculatus, 305 undulatus, 297 verrucosus, 306 zigzag, 327 Uniomerus tetralasmus, 287, 311, 340 Unionidae, 288-340 Unioninae. 288-312 United States Bureau of Commercial Fish- eries, 268, 286 United States National Museum {see also under individual species), 286, 313, 321. 333, 338, 339 University of Illinois Museum of Natural His- tory (see also under individual species), 286 University of Michigan Museum of Zoology {see also under individual species), 285, 286, 308 Upper Illinois River, 274, 333, 342-346, 363, 385 Utica, 295, 303, 310, 312, 318, 319, 327. 330, 339, 342. 349, 350 Valley City, 294, 299, 328 Vegetation, 342 Vermilion River, 333 Villosa iris iris, 287, 333, 340, 385 abundance and/or distribution, 333 pollution. 333 {=Micromya) iris, 333 w Wabash Pig-Toe {see Fusconaia flava forma flava) Wabash River, 268, 284, 306, 307, 324 Wading. 276, 284, 295, 320, 350. 362. 376- 377, 378, 380, 383, 393 Walleye, 336 Warmouth, 346 Warty-Back {see Quadrula nodulata and Quadrula pustulosa) Washboard {see Megalonaias gigantea) Waste treatment, 269, 343, 345, 346, 348, 353, 362, 363 Water chemistry, 273-275, 368-373 Weights, 276, 284 White bass, 296, 325 White crappie, 293, 299, 304, 325, 330-331, 334, 335, 338 White Heel-Splitter {see Lasmigona com- planata) White River, 291 Width index, 290, 291, 316, 317 Wisconsin River, 313 World War I, 274, 352 World War II, 267 Yellow perch, 299, 318, 325, 336 Yellow Sand-Shell {sec Lampsilis anodontoides forma anodontoides) Some Publications of the ILLINOIS NATURAL HISTORY SURVEY BULLETIN Volume 29, Article 2.—Stocking and Sport Fishing at Lake Glendale (Illinois). By Donald F. Hansen. July, 1966. 54 p., fron- tis., 9 fig., bibliogr., index. Volume 29, Article 3.—Hybridization of Four Species of Sunfishes (Centrarchidae). By William F. Childers. September, 1967. 55 p., frontis., 2 fig., color plate, bibliogr., in- dex. -The Thrips, or Thysa- By Lewis J. Stannard. frontis., 310 fig., bib- Volume 29, Article 4.- noptera, of Illinois. May, 1968. 338 p., liogr., index. Volume 30, Article 1.—Largemouth Bass and Other Fishes in Ridge Lake, Illinois, 1941- 1963. By George W. Bennett, H. Wick- liffe Adkins, and William F. Childers. Sep- tember, 1969. 67 p., 10 fig., bibliogr., in- dex. Volume 30, Article 2.—Dynamics of One- Species Populations of Fishes in Ponds Subjected to Cropping and Additional Stocking. By D. Homer Buck and Charles F. Thoits III. March, 1970. 97 p., 10 fig., bibliogr., index. Volume 30, Article 3.—Migrational Behavior of Mallards and Black Ducks as Deter- mined from Banding. By Frank C. Bell- rose and Robert D. Crompton. Septem- ber, 1970. 68 p., frontis., 25 fig., bibliogr., index. Volume 30, Article 4.—Fertilization of Es- tablished Trees: A Report of Field Stud- ies. By Dan Neely, E. B. Himelick, and Webster R. Crowley, Jr. September, 1970. 32 p., frontis., 8 fig., bibliogr., index. BIOLOGICAL NOTES 59.—Tables for Estimating Ages and Birth Dates of Cottontail Rabbits with Sugges- tions for Handling Lenses. By William R. Edwarji. December, 1967. 4 p., 2 fig. 60.—Use of Feather Minerals as Biological Tracers to Determine the Breeding and Molting Grounds of Wild Geese. By Har- old C. Hanson and Robert L. Jones. Feb- ruary, 1968. 8 p., 2 fig., bibliogr. 61.—Waterfowl Migration Corridors East of the Rocky Mountains in the United States. By Frank C. Bellrose. June, 1968. 24 p., 6 fig., bibliogr. 62.—Nightlighting : Its Use in Capturing Pheasants, Prairie Chickens, Bobwhites, and Cottontails. By Ronald F. Labisky. Octo- ber, 1968. 12 p., 8 fig., bibliogr. 63.—Selected Minerals in Soik, Plants, and Pheasants: An Ecosystem Approach to Un- derstanding Pheasant Distribution in Illinois. By Robert L. Jones, Ronald F. Labisky, and William L. Anderson. December, 1968. 8 p., 1 fig., bibliogr. 64.—The Value of In Vitro Fungicide Tests. By Dan Neely. January, 1969. 8 p., bibliogr. 55.—Trends in Pheasant Abundance in Illi- nois: 1958 to 1968. By Ronald F. Labisky. May, 1969. 8 p., 4 fig., bibliogr. 66.—Tree and Shrub Hosts of Verticillium albo-atrum. By E. B. Himelick. July, 1969. 8 p., bibliogr. 67.—Concentrations of Chemical Elements in Pheasant Tissues. By William L. Anderson and Peggy L. Stewart. April, 1970. 15 p., bibliogr. 68.—Illinois Birds: Mimidae. By Richard R. Graber, Jean W. Graber, and Ethelyn L. Kirk. September, 1970. 38 p., 32 fig., bibliogr. 69.—The Life History of the Dusky Darter, Percina sclera, in the Embarras River, Illi- nois. By Lawrence M. Page and Philip W. Smith. September, 1970. 15 p., 11 fig., bibliogr. CIRCULAR 46.—Illinois Trees: Their Diseases. By J. Cedric Carter. June, 1964. (Third printing, with alterations.) 96 p., frontis., 89 fig. 49.—The Dunesland Heritage of Illinois. By Herbert H. Ross (in cooperation with Illi- nois Department of Conservation). August, 1963. 28 p., frontis., 16 fig., bibliogr. 51.—Illinois Trees: Selection, Planting, and Care. By J. Cedric Carter. August, 1966. 123 p., frontis., 108 fig. 52.—Fertilizing and Watering Trees. By Dan Neely and E. B. Himelick. December, 1968. (Second printing.) 20 p., 9 fig., bibliogr. 53.—Dutch Elm Disease in Illinois. By J. Cedric Carter. October, 1967. 19 p., fron- tis., 17 fig. List of available publications mailed on request No charge is made for publications of the Illinois Natural History Survey. A single copy of most publications will be sent free to anyone requesting it until the supply becomes low. Costly publications, more than one copy of a publication, and publications in short supply are subjects for special correspondence. Such correspondence should identify the writer and explain the use to be made of the publication or publications. Address orders and correspondence to the Chief, Illinois Natural History Survey Natural Resources Building, Urbana, Illinois 61801