ERRATA. Page 12, lines 16 and 17, for one hundred read three hundred and for one thousand read six hundred. Page 17, line 2, dele first letter in the line. Page 168, line 12, page 177, lines 13 and 14, and page 271, line 10, for Lemna tnsulca read Spirodela polyrMza. Page 209, line 2 of foot-note, after hut insert represents. Page 2;'56, line 7, and page 266, line 19: snoioi n. s. has been shown to be hieroghjijhka, (^. Page 257, insert as line 8 as follows: -ken to the office produced young in ten days. The Page 272, line 13, for P. higuUatus read Pompiliis higuttatus. Page 278, Plate Y., 16, after view insert as follows: a, mentum; 6, labial rudiment; c, maxillary palpi; d, maxilla; e, labrum; /, antenna; g, eye; h, mandible. Page 286, line 11, drop initial the one line. Page 386, line 1, for Comstocki read Comstock. Page 399, line 17, for specimens read specimen. Page 411, line 10, for Michaelson read Michaelsen. Page 441, line 3 from bottom, for 66 read 68. Page 445, line 10 from bottom, for 57 read 5S. Page 466, line 1 from bottom, for Cyima read Oypris. Article Till.—Notes cm. Species of Xorth American Oli gochixta. By Frank Smith. A number of species of Oligochseta have been collected during the present year (j895) at Havana, 111., in con- nection with the work of the University of Illinois Bio- logical Experiment Station. It seems best to give a preliminary account of some of them at this time, al- though a more complete description, with plates, is in preparation. In this account is included some recently obtained information upon Enchijtrceus {Halodrilus) lit- toralis Verrill. Diplocardia ( Geodrilus) singularis Ude. In the months of April and May there were found at Havana, 111., many sexually mature earthworms which are probably identical with Gtodrilus singularis, described by Ude (14, p. 69)* from specimens collected at Danville, 111. Michaelsen (8, p. 190) has recently shown that a close sciutiuy of Ude's description makes it likely that the pores of the prostate glands are upon somites XVIII and XX instead of upon XVII and XIX, and that the male pore is upon XIX, and a letter recently received from Ude confirms the correctness of Michaelsen's as- sumption. The Havana specimens correspond to the description of G. singularis as thus amended, except in minor characters to be mentioned later. The poor state of preservation of Ude's specimens made a satisfactory account of the reproductive organs impossible. In having three pairs of spermathecse in VII, VIII, and IX, Diplocardia singularis agrees with D. communis Garman, and differs from the three remaining"^ *Here and throughout this paper the full-face parenthetical figures refer to the- bibliographical list which follows it. 286 IlUiiois State Laboratory of Natural History. species of the genus thus far described, while it agrees witli all but D. verrucosa Vde, (15) in the presence of prostate glands opening upon XVIII and XX. The prostate- gland pores are connected on each side by a longitudinal groove. The male pores are upon the anterior part of XIX. The clitellum is nearly as thick upon the ventral part of the somites as upon the dorsal, except upon XVII and XVI II. A pair of genital papillae is situated upon the posterior part of XVII or the anterior part of XVIII, and a second pair occurs upon XX or XXI, the position of both pairs being variable. The testes and ovaries and the funnels of the sperm •ducts are present in the usual number and situation, and the sperm sacs agree in number and arrangement with those of the other species of the genus. The dorsal vessel is single. The nephridia of the first pair are very small and open upon II. The position of the first dor- sal pore is not uniform, being in some specimens in the anterior part of IX and in others in the anterior part of X. In the other species of the genus I have found it in the anterior part of XI, where it is stated by Ude to occur in D. singularis. The penial setae of the specimens studied by me are long and slender, but have a slight double curve instead of the form figured by Ude (14, Fig. 18). The ventral setae are absent upon XIX, as the in some of the other species. The anterior end of worm is dark-colored upon the dorsal surface, as in D. ^iseni Mich, and in JD. riparia. Diplocardia riparia Smith, Since writing a previous paper (12) in which I described the above species and compared it in some particulars with Diplocardia {Geod/rilus) eiseni Michaelsen (8, p. 184), I have received, through the kindness of a friend in Florida, forty-one living specimens of D. eiseni which -were collected last June from the banks of Lake Eola in that state. A comparative study of these worms and Species of North American Ollgocfioeta. 287 of the D. riparia from Havaua shows clearly that they belong to distinct species; but it is necessary to revise somewhat the list of differences as given on p. 148 of my earlier paper (12). The two species agree in the presence of a pa:r of very small nephridia opening- upon 11, and also in the posi- tion of the first dorsal pore, which is in the anterior part of XI. The principal characters which distinguish the species are as follows: (1) The spermathecal pores are pos- terior to the seise in D. eiseni, while they are anterior to the setae in D. riparla; (2) the ventral setae of VIII and IX in D. eisini are modified and accompanied by glandular structures, while in D. riparia they are not; (8) the ventral sette of XIX are one or both present on each side of the somite in D. eiseni, but both are lacking in D. riparia; (4) the quadrangular glandular area upon the ventral part of XYIII—XX described by ]\Iichaelsen in D. eiseni is quite conspicuous in that species, but is not noticeable in D. idparia ; and (5) the two species are very different as regards size. On this latter point I may say that the specimens of D. eiseni received by me were quite uniform in size, and that none of them had a length of more than 150 mm. when alive and fully extended, the diameter of the an- terior part being only 2 mm. and that of the other regions still smaller. Michaelsen, on the other hand, gives IGO mm. as the length of one of his specimens and 3-3.5 mm, as the diameter, but this seems to have been exceptional, since he states that "andere Stiicke sind betrachtlich kleiner." Ordinary specimens of D. riparia are 220-250 mm. in length when fully extended, and 3 mm. in diameter. By comparing average speci- mens of each species I find the ratio between the weights of individuals of D. riparia and of those olD. eiseni to be more than 5:1. 288 Illinois State Laboratory of Natural History. Fridericia agilis u. sp. Numerous specimens of an enchytraeid worm belonging^ to the genus Fridericia were found at Havana, 111., asso- ciated with the different species of Diplocardia. They were sexually mature in April and May. The length of well-extended living specimens is 25-30- mm. and the number of somites is 57-66 in the specimens- examined, the average number being 62. The setae are straight, with the exception of a shght curvature of the proximal end, the usual number in each bundle being two, although sometimes one or even two- additional may be present in a few of the bundles. Occasional specimens are found in which between the^ ordinary setae of a pair a second pair of very slender ones is present, the diameter of the latter being one half that of the former, or even less. In such specimens this ar- rangement of setae prevails posterior to the clitellum as well as anterior to it. A head pore is present between the prostomium and peristomium, and the first dorsal pore is in VII. The clitellum is on XII and XIII. The posterior margin of the brain is quite convex, while its anterior margin is slightly concave. Its length is one and a half times its greatest width, and the posterior part is a little wider than the anterior. The salivary glands are large and very much branched, and open into the alimentary tract between its lateral and ventral walls in somite III. Septal glands occur in IV, V, and VI. The anteseptal part of each of the nephridia equals the postseptal part in size. The duct of the former is convoluted, and the terminal duct arises from the posterior end of the postseptal part and opens in front of the ventral setae. The dorsal vessel arises in XIX. The spermathecae communicate with the aliment- ary tract, each of them having about nine well-developed diverticula, which are hollow and somewhat unequal. The duct, which is about three times the length of the pouch, is slender, cylindrical, and without glands, except Species of JTorth American Oligochceta. 289 -a few scattering cells at the external opening. The length of the funnel of the sperm duct is about twice its diameter, and the duct itself is very slender, much coiled, and confined to XII. F. agllls is distinguished from the other species of the genus, except F. hlsetosa and the two species recently described by Nusbaum (10), by the number of setaB in each bundle, and it is distinguished from these by the form of the brain and by other characters. The spermathecse are more nearly like those of F. ollgosetosa, but the dissimilarity in the number of somites and of septal glands, together with the differences in the neph- ridia, in the duct of the spermathecse, and in the brain, clearly distinguish the two species.* Enchytrcsus {Ilalodrllus) littoralis Yerrill. Yerrill's description of this species (20, p. 623) contains no account of the reproductive organs, and consequently its relation to other Oligochseta has been quite uncertain. Vejdovsky (18, p. 45) placed it with the Tubificidse, while Vaillant (16, p. 292), Michaelsen (7, p. 50), and Beddard (1, p. 312) have considered it as an euchy- traeid. As a number of specimens, many of which were sexually mature, were obtained by me at Wood's Holl, Mass., in August of the present year (1895), I am able to extend the description somewhat. I think there is no doubt that these specimens belong to Yerrill's species, since they correspond very closely to his description and were extremely abundant in precisely the. same sort of situation in which he found his, namel}', in dead sea- weed and under stones near high-water mark, those under * Since the above description was written, an account of four new species of Friderioia from the vicinity of Philadelphia has been received from Mr. J. Percy Moore (Proc. Acad. Nat. Sci. Phil.. ISO.i. p. 341). Uf these F. longa is auite similar to F. agiJis in several characters. The arrangement of the setjB is somewhat different in the two species, and the number of diverticula of the spermathecaa Is somewhat greater in F. agilis than in F. longa, but the most obvious differ- ence is in the character of the salivary glands. Other differences may appear when more is known of the nephridia, the dorsal vessel, and the reproductive organs of the latter species. —19 290 Illinois State Lahoratm^y of Isatural Hintoiy. stones and in the sand being, as a general rule, raiicb smaller than those in the seaweed. The living animals are sufficiently transparent to en- able one to determine many facts concerning their struc- ture, and such observations have been supplemented by dissections and by the study of both longitudinal and transverse serial sections, which show the general anat- omy to be that characteristic of the Enchytrseidie. The length of the larger specimens is approximately 25 mm. and the diameter .5 mm. to 1 mm. The average number of somites in several specimens taken at random is 59, the minimum and maximum numbers noticed be- ing respectively 53 and 69. The setae are somewhat hooked at the proximal end, but are otherwise straight or sometimes slightly curved. The most frequent num- ber of setse in a bundle is three. There are often four present in the bundles of the anterior region, and some- times even six, but in the latter case they are in two sets of three each, as though a second set had been formed before the first one had been lost. In the bundles of the posterior region there are frequently but two setae present. The clitellum is on XII and XIII. I found no dorsal pores. The length of the brain is one and a half to one and three-fourths times its width, the ratio varying with the state of contraction. Its sides are nearly parallel, the anterior margin being slightly concave, and the posteri- or slightly convex or straight. A careful examination of this organ in several living specimens shows that the posterior margin is not concave, and that its convex or straight appearance is not due to the peritoneal cells, as suggested by Michaelsen (7, p. 36) in the case of E. vejdovshyi. Two long tubular unbranched salivary glands open into the alimentary tract upon its dorsal surface, behind the pharynx, and extend into IV, having a somewhat contorted course. Three pairs of septal glands occur in IV—VI, but those of V and VI are one Species of North AmeHcan OUgochcBta. 291 or both so constricted and contorted that there appear to be two pairs in each somite. I think that there is not the slightest doubt that these glands, together with the spermathecae, are the structures mentioned by Ver- rill as the csecal lobes of the alimentary tract, situated just behind the phai-ynx. There are certainly no exten- sive diverticula like those of some species of Henlea. The septal glands nearly surround the oesophagus, and this fact, together with the actual communication of the spermathecae with the oesophagus, would make it quite natural to assume that they were all thus con- nected if one should study living specimens only. The gland cells surrounding the oesophagus in VII and VIII are higher than those of the next following somites, and this fact probably explains Verrill's statement that the so-called eaecal lobes "are followed by a large two-lobed portion, beyond which the intestine is constricted." The dorsal vessel arises behind the clitellum, in XVII. The arrangement of the blood vessels in the anterior somites is the same as that described and figured by Michaelsen (6, p. 26; Taf. II., Fig. 2) for ''Enchytroem Mobii?'' The blood is colorless. The anteseptal part of each nephridium is small and forms the funnel only. The terminal duct arises from the posterior end of the post- septal part, and opens in front of the ventral setae. The spermathecae are without diverticula. The duct is of about the same length as the pouch, and is closely be- set with glands throughout its length. The length of the funnel of the sperm duct is several times its diam- eter. The duct itself usually extends to XVII or XVIII in a tolerably straight course, and then, making a short, abrupt turn, retraces its course, the second part lying close beside the first, and communicating with a small prostate gland in XII. As one traces the duct from the funnel, the diameter is nearly uniform until just after the turn, where it is nearly doubled, the size being again uniform until a point is reached about one third of the 292 Illinois State Laboratory of Natural History. distance from the prostate gland to the turn. From this point the diameter gradually diminishes, and be- fore reaching the prostate, becomes smaller than in any other part of the duct. The diameter of the widest part of the duct is one fifth that of the entire worm in that region, and three times the diameter of its own lumen. In specimens that have passed the period of sexual activity the sperm duct becoiiies reduced in size, more convoluted, and extends backward a shorter distance. JSnchytrcBus littoralis is evidently very closel}' related to E. vejdovsJcyi Eisen (3, p. 25) and E. Immicultor Vejdov- sky (17, p. 57). The chief difference would seem to be in the sperm duct, which in E. littoralis extends back as far as XVIII, but which at the height of sexual activity is entirely free from the numerous flexures described by Eisen (3, Fig. 19h), Michaelsen (6, p. 39; and 7, p. 37), and Ude (13, p. 86) as existing in E. vejdovshyi and E. himiicultor. Specimens of E. littoralis are frequently found in which the sperm duct passes from one side of the body to the other once or sometimes twice, but it is without sharp turns except at the point farthest back, where its course is reversed. The somewhat abrupt in- crease in the diameter, already described, is also very characteristic. The brain is similar in form to that of E. vejdovsl'yi as figured by Eisen (3, Fig. 19f), though less concave in front and less convex behind. In view of the above facts it seems reasonable to question the ad- visability of regarding the differences between the Euro- pean and American forms as more than varietal. Ver- rill's name has priorit3% of course, in the event of its being necessary to unite the species from the two con- tinents under one name. Thinod/rikis hiconstans, n. g. et n. sp. At various times since April 1894 specimens of a spe- cies belonging to the Lumbriculidae have been collected from the east shore of Quiver Lake, at Havana. They Species of North American Oligochceta. 29'3 «.re sometimes found in the algie, sometimes in the mud •at the bottom of the lake, and sometimes on the shore above the level of the water, under rubbisli which is kept moist by the springs constantly flowing from the bank. Among specimens collected last February from a situa- tion like that last described, one individual was found that was sexually active, with others that had been in that condition recently' enough to be of use in gaining a knowledge of the sexual organs. The worms are 30-60 mm. in length and .6-.8 mm. in diameter. The number of somites is usually 150-200, and sometimes even greater. The setae are in four rows of i)undles with two setae in each. They are .15-2 mm. in length, with bifid extremities, and have the same form as those of Ltimhricuhis variegatiis Grube as figured by Vejdovsky (18, Taf. XII, Fig. 27). The length of the prostomium in alcoholic specimens is about equal to that of the first three somites taken together, and its width is almost as great as the diameter of the first somite. The width is nearly uniform for the greater part of the length, and the extremity is bluntly rounded. The brain is quite similar to that of L. variecjatus Grube as figured by Ratzel (11, PI. XLII., Fig. 10), if T under- stand his figure, but not if Beddard's interpretation (1, p. 212) be correct. A comparison of Ratzel's figure 10 with figures 12 and 13 of the same plate makes it quite evident that the supracesophageal ganglia are repre- sented by Ratzel in a position the reverse of the nor- mal one, so that what is described by Beddard as the anterior part is really the posterior part, and vice versa. In the brain of Thmodrilus inconstans the masses of cells are upon the posterior part, and are not united by a narrow layer of cells as represented in lAmibriaidus vari- egatiLS, although such a layer is present upon the outer surface of the brain, and if no sections were made might be supposed to connect the two masses. The median part of the brain, which connects the two lateral 294 Illinoid State Laboratory of Natural History. divisions, is composed entirely of fibers with the excep- tion of a few cells in the dorsal part. Groups of cells are situated respectively in front of and- behind the^ point of union of the commissures with the ventral chain. The pharynx extends through II—V and is fol- lowed by the oesophagus in VI and VII, and in VIII by the intestine, which, as indicated by the chloragogue cells, commences in that somite. The septal glands are large in IV—VI, and slightly developed in III. Beginning with the eleventh somite, paired appenda- ges of the dorsal vessel with several caecal branches are present. Nephridia are contained in the same somites with the gonads at the time of maturity of the latter. No especial modification of the epidermis to form a clitellum has been noticed. Albumen glands are want- ing. Two pairs of testes are present in IX and X and two pairs of ovaries in XI and XII. The male pores were determined with certainty in but three specimens, in two of which the pores were upon X and in the other upon XI. The atria are similar in form and in the structure of the walls to those of L. variegatus as de- scribed by Hesse (4, p. 358) and by Vejdovsky (19, p. 81). Whether or not a definite penis is developed I am unable to state. The funnels of the sperm ducts are borne upon the posterior walls of IX and X. The sperm ducts have not yet been followed throughout their en- tire course. A pair of elongated sperm sacs communi- cate with X and extend backward for a varying num- ber of somites, in some cases as far as XX. Well- developed spermathecse were found in but one specimen, and in that did not contain spermatozoa. There are five pairs in XI—XV, with their pores dorsad to the ventral setae and situated similarly to those of L. va/riegatus. In another example vestiges of these organs were present in XI—XV, while the specimen hav- ing male pores upon XI had traces of spermathecae in XII—XVI. The oviducts are short and open at the Species of North, American OligochcBta. 295 posterior margin of their somites XI, XII. In all the specimens examined gonads were present in TX—XII. No attempt will be made at present to distinguish fully between generic and specific characters. The characters of the setae and of the branches of the dorsal vessel distinguish Thinodrilus inconstans from other Lumbri- culidae except Lumbriculus, while the number and posi- tion of the various reproductive organs distinguish it from that genus. Its relation to Lumhriculus llmosus Leidj (5, p. 49) cannot be determined until more is known of that species. It seems probable enough that they may belong to the same genus, though I do not think that they are identical if the setae of L. limosus are correctly figured by Leidy (5, PI. 2, Fig. 16), since the distal portion is much more curved in his figure, and the point of abrupt change in diameter is considerably nearer the distal end than in the setae of Thinodrilics inconstans. Also, the number of caecal appendages of the dorsal vessel is greater than I have noticed in the latter species. In spite of these differences, how'ever, there is a possibility that the forms may prove to be identical. The genus Diplocardia apparently'" contains five dis- tinct species, and is distributed over an area extending from Florida at least half way across the continent. Sparganophilus has several species and at least as wide a distribution. Benham (2, p. 175) suggests tliat the occurrence of S. tamesis in England is due to its importation, presumably from America, which seems highly probable, especially as Moore (9, p. 473) reports the occurrence of that species near Philadelphia. Bimas- tos is very distinct from the European Lumbricidae. In view of the above facts, the distinctness of the Palae- arctic and Nearctic regions as shown by the earthworm fauna would seem greater than has previously been sup- posed. I take this opportunity to express my gratitude to Prof. E. L. Mark, of Harvard University, through whose 29G Illinois State Laboratory of Natural History. kindness I have been permitted to work during the past summer in the laboratory and library of the Museum of Comparative Zoology, and especially to Prof. S. A. Forbes, of the University of Illinois, whose continued encouragement and assistance have enabled me to carry on m}^ study of this interesting group of animals. Champaign, Dec. 12, 1895. LIST OF PAPERS CITED. 1. Beddard, F. E.—A Monograph of the Order Oli- gochoeta. 1895. 709 pp., 5 plates. 2. Benham, W. B.—A New English Genus of Aquat- ic Oligochaeta (Sparganophilus), belonging to the Family Rhinodrilidse. 1893. Quart. Journ. Micr. Soc, Vol. XXXIV., pp. 155-179, PI. XIX. and XX. 3. EiSEN, G.—On the Ohgochaeta collected during the Swedish Expeditions to the Arctic Regions in the years 1870, 1875, and 1876. Kongl. Sv. Vet.- Akad. Handl., Bd. 15, No. 7. 1879. 4. Hesse, R.—Die Geschlechtsorgane von Lumbricu- lus variegatus Grube. 1894. Zeit. f, wiss. Zool., Bd. LVIIL, pp. 355-363, Taf. XXII. 6. Leidy, J.—Descriptions of some American An- nelida abranchia. 1850. Journ. Acad. Nat. Sci. Phil., Vol. II., 2d ser., pp. 43-50, PI. II. 6. Michaelsen, W.—Untersuchungen liber Enchytraeus Mobii Mich, und andere Enchytraeiden. Kiel, 1886. 50 pp., 3 Tafeln. 7. Synopsis der Enchytraeiden. 1889. Ab- handl. d. Naturw. Ver. Hamb., Bd. XL, Heft I., 60 pp., 1 plate. 8. Die Regenwurm-Fauna von Florida und Georgia. 1894. Zool. Jahrb., Abth. f. Syst. Bd. VIIL, 2 Heft, pp. 177-194. Sjpecies of North Amtvlan Oligoclneta. 2\)1 9. Moore, H. F.—Oq the Structure of Bimastos pa- lustris. a New Oligochrete. 1895. Journ. Morph. Vol. X., No. 2, pp. 473-49G, PI. XXVI. and XXVII. 10. NusBAUM, J.—Z ir Anatomie und Systematik der EucLytraeiden. 1895. Biol. Ceutr., Bd. XV., No. I., pp. 25-31. 11. Katzel, F.—Beitrage zur anatomiscliPii und sys- tematisehen Kenntniss der Oligochaeten. 18G8. Zeit. f. wiss. Zool., Bd. XVIII., pp. 563-591, Taf. XLII. 15. Smith, F.—A Preliminary^ Account of two New OligocliEeta from Illinois. 1895. Bull. 111. State Lab. Nat. Hist., Vol. IV., Art. V., pp. 138-148. 13. Ude, H.—Wiirmer der Provinz Hannover. I. 1892. Jaliresb. Nat. Ges. Hann., pp. 63-98, 1 plate. 14. Beitraii'e zur Kenntnis auslandischer Reg*- enwiirmer. 1893. Zeit. f. wiss. Zool., Bd. LVII., pp. 57-75, Taf. iV. 15. Uber zwei neue Lumbriclden-Arten aus Nordamerika. 1895. Zool. Anz. Jahrg. XVIII., No. 483, p. 339. 16. Vaillant, L.—Plistoire naturelle des Anneles niarins et d'eau douce. Tome III., Prem. Part. 17. Vejdovsky, F.—Beitrage zur vergleicheuden Mor- phologie der Anneliden. I. ^tonographie der En- chytraeiden. 1879. 61 pp. 14 plates. 18. — System und Morphologic der Oligochae- ten. 1884. 166 pp., 16 plates. 19. Zur Kenntnis des Geschlechtsapparates von Lumbriculus variegatus. 1895. Zeit. f. wiss. Zool. Bd. LIX., pp. 80-82. 20. Verrill, a. E.—Report upon the Invertebrate Animals of Vineyard Sound and the Adjacent Waters. 1873. Rep. U. S. Fish Comm. 1871-72, pp. 295-778, 38 plates.