c:jC^

BULLETIN

Illinois Qtate I aboratory

OF

NATURAL HISTORY

Urbana, Illinois.

VOLUME V.

ARTICLE X. N.OTES ON SPECIES OF NORTH AMERICAN
OLIGOCHAiTA. III. LIST OF SPECIES FOUND IN
ILLINOIS, AND DESCRIPTIONS OF ILLINOIS TUBIFIC-
ID.E.

By frank smith, A. M.

Illinois State Laboratory of Natural History.

IKBANA, ILLINOIS.

March 21, 1900.

'Us

-.7



WITH THE COMPLIMENTS OE

FRANK SMITH
UNIVERSITY OF ILLINOIS, URBANA, ILL.., U. S. A.



ERRATA.

Page 136, line 2, and jiage 182, line 17 from bottom, f(jr 'g^a read 'gj.

Page 226, line 2, page 263, line 17 from bottom, and page 267, lines

2 and 15, for 'g8, read 'g6.

Page 233, line 15 from bottom, for '82 read '82a.

Page 355, line 2 from bottom, for C. F. Hudson read C. T. Hudson.

Page 389, foot-note, for Vol. V. read Vol. IV.

Page 457, line 5, for Genera read Genus.

{



Article X.

—

Notes on Species of North American Oligochfcta.

III. List of Species found in Illinois, and DescrijHions

of Illinois Tuhijicidce. By Frank Smith.

The study of Illinois Oligochceta has been mostly confined

to collections of the Illinois State Laboratory of Natural

History, made near the Biological Station at Havana, 111.,

and in the vicinity of the University of Illinois, at Urbana

;

it is probable, therefore, that several species occur in the

State which are not included in the following list. Thus far

no attention has been given to the Diseodrilidu and but

little to the Enchytneidce of the State.

A list of the earthworms found in North America was pub-

lished in 1888 by Garman in Vol. III. of this Bulletin, in

which those mentioned as occurring in Illinois are three

species of Luvibricidce, one of Acanthodrilid<e, and one of

Periclueta which had become established in the University

greenhouses. To these must now be added seven other

species, most of which have been described since Garman's
paper appeared.

The species recorded have all been identified by the writer,

but a considerable part of the detailed study of sections of

the two new species of TubificidiC here described has been

made by a student of the University of Illinois, Miss Ella V.

Engstrom, whose careful work has been of material assistance

in the preparation of this paper. The drawings for the

figures were made by Miss Lydia M. Hart, Artist of the

Illinois State Laboratory of Natural History.

LIST OF SPECIES.'

Lnmbricidce.

Lumbricns hercideii.s Savigny. Urbana ; infrequent.

Allolohojjhora foetida Sa,yigny . Urbana; abundant.

Allolohojyhora rosea Savigny.- Urbana; frequent.

Allolohopliora profucja liosa. Urbana; abundant.

' The classification of families is that adopted by Beddard in his Monograph.
" yl. niMcosrt Eisen. 441



442 Illinois State Laboratory of Natural History.

Allolobophora caliginosa trapczoidcs Duges.^ Urbana and
Havana ; abundant.

Allolobophora &^ .'^ Urbana and Havana ; frequent.

Geoscolicidce.

Sparganophilus eiseni Smith. Urbana and Havana;
abundant.

Acanthodrilidce.

Diplocardia communis Garman. Urbana ; abundant.

Diplocardia riparia Smith. Havana ; abundant.

Diplocardia singularis Ude. Urbana and Havana ; fre-

quent.

Diplocardia sTp.^ Havana; frequent.

Lumbriculidce.

Thinodrilus ineonstans Smith. Havana ; abundant.

Mesoporodrilus asymmetricus Smith. Havana ; infrequent.

Phreoryctidce.

Phreoryctes emissarius Forbes. Urbana, infrequent;

Havana, abundant.

Ejichytrceldce.

Fridericia agilis Smith. Havana ; abundant.

Tiibijicid(e.

Tubifex rivulorum Lamarck. Urbana and Havana

;

abundant.

Limnodrilus claparediauus Eatzel. Urbana and Havana

;

abundant.

* A. turgida Garman, non Eisen.

= A species closely allied to A. giesleri Ude, but its exact relationship has not yet
been determined.

3 A species closely allied to D. verrucosa Ude. Exact relationship not yet
determined.



Illinois Oligochceta. 443

Rhizodrdns lartcKs u. g. et n. sp. Havana ; abundant

locally.

Emholocephaliis inultisctosus n. sp. Havana; abundant

locally.

Naidomorpha.^

Nais lacustris Linnaeus. Urbana and Havana; abundant.

Nais elinguis 0. F . Miiller. Urbana and Havana ; abundant.

Nais lurida Timm. Havana ; frequent.

Nais serpentina 0. F. MiiWer. Havana; frequent.

Dero limosa Leydig.* Havana ; abundant.

Dero ohtusa D'Udeke-m. Havana ; abundant.

Dei'o vaga Leydig. Havana ; abundant.

Dero furcata Oken. Havana; frequent.

Pristina leidyi Smith. Havana; abundant.

Pristina Jiagellnm Leydig' Havana ; one specimen.

Chcetogaster limiuei v. Baer. Havana ; abundant.

Chatogaster diaj)hanus Gruithuisen. Urbana and Havana
;

abundant.

Chatogaster diastrophns (j[xm.i}ivi\Qen. Havana; abundant.

jEolosomatidif

.

.'Eolosoma hemprichii Ehrenberg. Urbana and Havana;
frequent.

jEolosoma ifnt'&rant»< Vejdovsky. Havana; abundant.

jEolosoma B^:^ Havana; abundant.

DESCRIPTIONS OF TUBIFICID.E.

As the first two species of Tuhificidce in our list are well-

known European forms which have been described at length

by previous writers, a brief recapitulation of some of their

more important characters will suffice in this connection.

' But little attention has been given to the Naidomorph.a of Urbana.
= A species with colorless integumental globules, not yet described.

^B'Or Leydig, read Lieidy.



444 Illi)iois State Tjalioniforn of NatKVdl History.

Tnbifex riciilorioji Lamarck.

Length 25-50 mm.; number of somites 50-60. Dorsal

bundles with three kinds of set^e : capilliform setee, four or five

per bundle anterior to clitellum, decreasing in number pos-

teriorly and absent from the last few somites
;
pectinate setae,

in somites anterior to the clitellum ; and uncinate setae in

other regions. Ventral bundles with four or five uncinate

setae in anterior part and fewer posteriorly. In Illinois

specimens the ventral bundles sometimes contain pectinate

setae. No ventral setae on XI. Clitellum on XI and most of

XII. Alimentary tract spiral-like in appearance, but with

dorsal vessel on the upper side throughout its course. One

pair of " hearts " in VIII. First nephridium in VII. Penis

with a very short delicate chitinous sheath near tip.

Limnodrilus claparedianus Ratzel.

Length 40-70 mm. ; number of somites 145-160. Setae

all uncinate ; five to seven per bundle in anterior part, fewer

posteriorly. Clitellum on XI and XII. " Hearts " in VIII.

Penis with chitinous sheath .5-1 mm. in length, which is

twenty to thirty times its diameter.

Rhizodrilus lacteus n. g. et n. sp.

The species bearing this name is fairly abundant in Flag

Lake, one of the larger bodies of water occurring in the bot-

tom-lands of the Illinois Piiver near Havana, 111. Nothing

is known of its distribution in other regions. Specimens have

been found in considerable numbers among the roots of sub-

merged or partially submerged Sagittaria variahilis, but thus

far in no other situation. They are sexually mature in July.

The worm is rather sluggish in habit, and the body is

usually contorted and in an almost inextricable tangle. It

varies from 70 to 100 mm. in length in sexually mature

individuals ; is quite slender, varying from .4 to .6 mm. in

diameter; and is largest in the region of the reproductive

organs. The body is nearly white, owing to the great number



Illinois Oligoihcta. 445

of ccflomie corpuscles with which the coelomic riuid is crowded,

and which are readily visible through the delicate walls. In

nine specimens, apparently complete, the number of somites

varies from 215 to 3G5, the average number being 281.

The seta', except the genital ones, are all of the ordinary

uncinate, or cleft, type, and have the usual arrangement of

four bundles to each somite. Anterior to the clitellum the

number of setre in each bundle is usually five or six, but

posterior to it, throughout the greater part of the length, the

number is commonly four, while near the posterior end it is

more frequently one to three. The ordinary uncinate setae

are slightly enlarged at a point about one third of their length

from the outer extremity. They are usually .09 to .1 mm.
in length and about .005 mm. in diameter at the middle.

The genital setae are of two kinds. On the ventral side of IX,

in place of each bundle of ordinary setae, there is a specially

modified seta (PI. XXXIX., Fig. 4, b, and PI. XL., Fig. 6—
viewed in different planes) .12 mm. in length and about .01

mm. in diameter at its largest part, which is near the proxi-

mal end. These seta' are in close relation to the openings of

a pair of glands to be described later. In one specimen ven-

tral setae of the same sort were present in X. The ventral

bundles of XI each consist of four to six peculiarly shaped

setae entirely different from the ventral setae of IX, the outer

end of each being spatulate and rather abruptly bent (Fig.

4, c). These setae are from .14 to .16 mm. in length, and the

diameter is about .009 mm. at the inner end and .006 mm.
near the expanded outer end, while the outer end itself is

about .01 mm. in width.

The clitellum is of the same general character as the clitel-

lum present in other Tuhijiciihf , and extends from about the

middle of X to the posterior part of XII, in some individuals

encroaching on XIII. It is incomplete ventrally. The pros-

tomium is relatively large and subconical.

The brain has a slightly convex anterior margin, without

any such median anterior extension as is present in some

Tnhificidce. There are two posterior lobes extending back-

wards, one from each side of the middle of the ventral margin.



446 Illinois State Lahoratory of N(ittir<(l History.

The pharynx extends through somites II and III, and its

dorsal and ventral walls are of about equal thickness. The

CESophagus extends backwards into VI, where the epithelium

gradually assumes the character of that of the intestine. In

VII the alimentary tract increases in diameter, and the intes-

tine may be regarded as commencing in that somite. Septal

glands are present in IV and V, those of the latter somite

being the smaller. Ccelomic corpuscles are very numerous

in the ccelomic spaces not otherwise filled. They are spherical

and mostly without granular contents, although some contain

a few rather large spherical granular bodies.

The circulatory system cannot be studied in the living

worm because of the opacity due to the numerous corpuscles,

and our knowledge of it is chiefly derived from a study of

transverse and longitudinal sections. ' The dorsal and ventral

vessels do not divide in the anterior region of the body to

form supra- and sub-intestinal trunks. In the posterior part

of each of somites VII-X a pair of large lateral vessels, or

"hearts," is present, connecting the dorsal and ventral ves-

sels directly, without giving off branches to the body wall as

is the case in Ilyodrilits. These vessels are approximately

equal in the somites mentioned. The diameter of the lateral

vessels of VI is only about one fifth as great as that of the

corresponding vessels of VII.

The nephridia have been studied with reference to charac-

ter and arrangement in but three individuals,' and in these

only in the anterior twenty somites. These organs first

appear in VIII, but in VIII, IX, and somites posterior to XI

only one nephridium is present in each somite, and that is in

the left side of the body in all cases observed. In sexually

mature individuals nephridia are absent in X and XI. The

ventral vessel lies in the left side of the body, and is closely

invested by the expanded glandular part of each nephridium,

the relation between them being much like that described by.

Goodrich as existing in Vermiculus pilosus ('95, p. 258).

The nephridium enlarges almost immediately behind the

anterior septum, forming a mass of considerable size, through

which the duct passes in a tortuous course, finally leaving the



Illinois Oligochceta. 447

main mass at a point a little anterior to the middle and
extending to the body wall in a latero-ventral and posterior

direction, opening a little anterior to the inner margin of the

ventral bundle. Absence of nephridia from one side of the body
in several successive somites has been frequently observed

in Naidomorpha (Benham,'93, p. 385, and Smith, '96, p. 398)
and occasionally in the Tuh\ficid(c (Stole, '88, p, 23). In

nearly all the species of Tnhificida' studied by this latter

observer he found rare cases in which one of the nephridia of

some somites was entirely degenerate, and others in which a

whole row of nephridia on one side, especially in the last

somites, was less developed than the row of the other side. In

Rhizodrilus lacteus this degeneration has gone still further,

so that a row of nephridia on one side is entirely wanting.

The testes are in the anterior part of X, in the usual posi-

tion, and the spermiducal funnels are in the posterior part

of this somite, the sperm- ducts leading from them into XI
and opening on its ventral side. Following the sperm-duct

backwards from the point of entrance into XI, it is at first of

small diameter, with relatively thin walls, and extends pos-

teriorly and somewhat veutrally for a distance equal to one

sixth the length of the somite. Bending then abruptly toward

the dorsal side of the somite it passes directly upward to the

dorsal wall, and then extends in a posterior direction to a

point slightly beyond the middle of the somite, where it bends

toward the ventral side, opening on the antero-lateral wall of

a spermiducal chamber into which opens also the sperm-

duct of the other side. (PL XXXIX., Fig. 5.) From the

point at which the sperm-duct bends towards the dorsal wall

throughout the rest of its course the lumen remains of small

diameter. From this same point on, for nearly its whole

length, the walls are greatly thickened, so tbat the diameter

of the duct is nearly one third that of the entire somite. A
short distance from the spermiducal pore the walls become
thin again. There is no enlargement of the lumen to form
an atrium, nor any modification of the wall in any special

region to form a prostate gland, nor is there a penis. The
great diameter of the duct throughout most of its length is



448 Illinois State Laboratory of Natural History.

due to the glandular peritoneal layer which is formed of

much-elongated cells.

The spermiducal chamber, already mentioned, is formed

by an invagination of the mid-ventral wall of XI posterior to

the middle of the somite. Its lateral walls are connected

with the body wall by muscular strands which control their

movements. When the form of this chamber is normal the

innermost part is transversely elongated, and the outer part

has its greatest length parallel with the long axis of the body

;

but at times the lateral walls may be pulled far apart, the

chamber thus becoming merely a ventral depression. It

seems probable, therefore, that the structures are chiefly

functional during copulation. The wall of the chamber

includes a cuticula, continuous with that of the body wall,

a layer of hypodermis but slightly modified, and a layer

beneath the hypodermis which is quite thick and includes

many large cells, perhaps of a glandular nature, the contents

of which are usually nearly transparent, though sometimes

of a granular character. The peculiar genital setse already

referred to as constituting the ventral bundles of XI are

borne on the posterior wall of the spermiducal chamber, into

which they project.

But one sperm-sac is present. It extends from its opening

in the dorsal part of septum X/XI into XY or XVI. In the

somites posterior to XI it is included in the ovisac. The

anterior septum of X is sometimes pushed far forward into

IX, but there is no anterior sperm-sac.

Ovaries are present in the usual situation, in the anterior

part of XL The oviducal funnels and oviducts are small but

fully developed, and situated between XI and XII. The

single ovisac extends backwards from its opening in the

dorsal part of septum XI/XII into XVII or XVIII. The ova

develop in the same manner as in the majority of the Tuhi-

ficidce, and not as in Ilyodrilus and Naidomorpha.

Two spermathecffi are present in the anterior part of X.

Each of them has a sac, nearly spherical in outline, which

communicates with the exterior through a short duct (PL

XL., Fig. 7) opening on the anterior margin of X at a point



Illinois Oligochceta. 449

dorsad of a line connecting the ventral bundles of one side.

The interval between the two spermathecal pores is about

one fourth of the circumference of the body. The sperma-

tozoa in the spermathecae are present in loose masses. No
signs of spermatophores have as yet been found.

A pair of elongate tubular glands is present in IX, their

openings being in close relation to the peculiar genital setae

of that somite (PI. XL., Fig. 6). In the specimen previously

referred to as having genital setae on X similar to those on

IX, a pair of such glands is also present in X, having similar

relations to the setae of the somite. These glands are about

equal in length to the somite, and their diameter, which is

nearly uniform throughout their length, is about one eighth

the diameter of the somite. The diameter of the lumen is

about .01 mm. and the walls are .03 mm. in thickness. The

wall consists of two layers of cells, the outermost being very

thin and composed of flattened epithelial cells, while the

inner layer is formed of relatively large glandular cells,

largest at their distal ends, in which the nucleus is com-

monly situated. The openings of these glands and the asso-

ciated setae are on prominent rounded elevations of the ventral

wall of the somite (PI. XL., Fig. 6) and in line with the ventral

setae of adjacent somites. On the summit of these elevations

the hypodermis is modified as it is in the genital papillae of

some earthworms ; for example, Diplocardia {\ndi Allolohophora

.

For the sake of greater convenience in the comparison of

R. lartciis with other forms I give the following summary of

its more important characters :

The number of somites is 215-305.

All the setae are uncinate except the genital ones, which are

of two kinds, one form in IX and the other in XL
The clitellum extends from the middle of X to the posterior

part of XII.

Gcelomic corpuscles are very numerous.

Supra- and sub-intestinal vessels are wanting, and the

lateral vessels or "hearts," which connect the dorsal and ven-

tral vessels in VII-X, are enlarged, nearly uniform in size,

and do not give off In-anches to the l)ody wall.



450 Illinois State Laboratory of Natural History.

The nephridia closely invest the ventral vessel, and, so far

as observed, but one nephridium is contained in a somite.

The sperm-ducts have no prostate gland, atrium, or penis,

and open into a median spermiducal chamber on the ventral

side of XI.

A pair of spermathecse is present in the anterior part of X,

and the spermathecal pores are a considerable distance from

each other.

A pair of elongated tubular glands is present in IX, opening

in close relation with the genital setae of that somite.

No attempt has been made to distinguish between generic

and specific characters, since only one species of the genus

is known. From the foregoing it is apparent that Rhizodrilus

lacteus is somewhat closely related to Lumhriculus sjnralis of

Leidy ('52a, p. 285) in respect to length, number of somites,

form and character of setae, color, and habits ; but as Leidy's

description is entirely inadequate for the purpose of identifi-

cation, and as he left no type specimens of his species, the

relationship between the two forms cannot be determined. It

is unfortunate that the description of a new species of Tuhi-

ficidce so frequently involves the description of a new genus, but

according to present ideas of the classification of this family

the character of the species under discussion will not permit

its inclusion in any existing genus. The presence of two

distinct kinds of highly modified genital setae and the pres-

ence of such setae in the ninth somite distinguish this worm
from all other described forms of Tiihijicid<e. In the absence

of distinct prostate glands and in the presence of a common
spermiducal chamber it differs from most Tiihlficidce but

resembles Vermiculus. There is a further resemblance to the

latter genus in the simplicity of the longitudinal blood-vessels

and in the absence of both supra- and sub-intestinal vessels,

but the relation of the lateral vessels of the anterior somites

to other parts is very different in the two genera. In Vermic-

ulus pilosus, in II-X there is no direct communication

between the dorsal and ventral vessels, the single pair of

branches of the dorsal vessel in each of those somites break-

ing up into a capillary network in the body wall, from which



Illinois Oligoch(Eta. 451

the blood is conducted to the ventral vessel through two pairs

of vessels in each somite, of which the posterior pair is the

larger. In V.limosus, recently described from Japan by

Hatai ('98, p. 110), the same general relation exists between

these lateral vessels and the body wall, except that there is

but one pair of lateral branches of the ventral vessel in each

of the somites referred to, and that there is a slight differ-

ence in the number of somites in Avhich such vessels occur.

Goodrich ('95, p. 262) regarded this condition of the circu-

latory system as distinguishing Vcrmicnlus from all other

Tnhificiihe . The circulatory system of Ilyodrilus coccineus,

as described and figured by Stole ('88, p. 15, Tab. IL, Fig. 9),

seems to constitute a very interesting intermediate type

between that of 'fcrinieiilus and such forms as Bhizodrilus.

As Stoic's paper is unfortunately written in Czech, it has

been inaccessible to most students of the Olujocha'ta

,

Through Mr. L. F. Miskovsky, of Oberlin College, I have

been so fortunate as to obtain a very careful translation of

this admirable paper, and quote here that part which treats

of the vascular arches of Ilyodrilus.

"In the following segments, i. e., in the fourth to the ninth

inclusive, the dorsal artery is united with the ventral always

through one pair only of lateral arteries, which issue before

the posterior septum of each somite from the dorsal artery

and gradually swell behind until in the last three of the

named segments they assume the largest proportions, resem-

bling thus the swelled lateral arteries (so-called hearts) which

are found in the remaining genera of the Tubijicida-. The

Literal arteries here described do not, however, open simply

into the ventral artery. Each one of the lateral arteries

approaches closely to the lateral diameter of the body and

sends several branches into the integument. The branches

running through the integument form in each segment an

elegant vascular network which is connected through numer-

ous anastomoses with the plexuses of the other segments.

The sanguineous fluid after coursing through this integument-

ary network returns into the ventral vein through two special

veins, which, issuing out of the integument from the lateral



452 Illinois State Lahorntory of Natural History.

diameter of the body, after a short course, empty into the

ventral vein."

Figure 9 of Plate II in Stoic's paper is a diagrammatic

representation of the circulatory system in the anterior part

of /. coccineus. Through some typographical error that part

of the description of plates dealing with this figure is headed

Bothrioneuron vejdovskyamnn, and is thus somewhat confus-

ing. A comparison of this figure with that of the correspond-

ing organs of Vermiculus pilosus (Goodrich '95, PI. XXVI.,

Fig. 5) and Rhizodrilus lacteus (PI. XL., Fig. 8) will readily

suggest a common derivation for the different types. For

convenience in making such comparison Figures 9 and 10 of

Plate XL. have been prepared from the figures by Goodrich

and Stole.

Emholocephalus multisetosus n. sp.

"Worms of a species of Tuhificidce not hitherto described

are found in great abundance in the vegetable debris at the

bottom of Flag Lake, and are occasionally met with in the

vegetation along the banks of the Illinois River and the bot-

tom-land lakes in the vicinity of Havana.

Well-extended individuals are 19 to 35 mm. in length. At

the time of sexual activity a few somites at the anterior end,

including the reproductive organs, are much enlarged, the

diameter of the worm in this region being then two and a half

or three times that of the remainder of the worm. In a rather

large specimen the diameter in the region of the tenth somite

is .8 mm., that of the middle of the worm is .3 mm., and at a

distance from the posterior end equal to one fourth the length

of the body the diameter is .2 mm. The number of somites

varies from 49 to 106 in specimens examined, but 75 to 80

is more common. The main part of the body is of a dark

grayish color, but the posterior end is lighter and less opaque.

A sheath formed in part of foreign particles cemented together

envelops the anterior part of the body, making it quite opaque.

It adheres very closely to the surface of the worm and is

removed with great difficulty. It is wanting in the posterior

part of the Ijody, which is extended into the open water and



Illinois Oligochceta. 453

is, as in many Tuhificida', the principal respiratory region.

Non-retractile sense papilhe similar to those described for

Emholocephalus, Spirospcrma, and a few other Tuh'ific-id<e, are

preseat in this species. They are arranged in two rows on

each somite, one row coinciding with that of the setse bundles

of the somite, and the other one being usually in the plane

of the septum (PL XXXIX., Fig. 1). A few papillfe repre-

senting a third, very incomplete, row are often present.

When a specimen is examined with a lens, one is strongly

reminded of some of the marine annelids by the dense clusters

of elongated setse in the dorsal bundles. The dorsal setffi are

of two kinds; long capilliform setai, often .5 mm. in length,

and palmate or comb-like setffi .16 to .18 mm. in length

(PI. XXXIX., Fig. 2, c, d.). In the anterior bundles capilli-

form sette vary in number from three to fourteen per bundle.

Throughout most of the remainder of the body the number
is but one to three per bundle, while the last ten to twenty

somites usually have no dorsal sette whatever. The palmate

setae are regularly found in only a few anterior somites,

where the number varies from one to five per bundle. In the

dorsal bundles of the greater part of the body back of the

first ten or twelve somites, palmate setae are usually lacking,

though occasionally one such may be found in one or more

bundles posterior to the middle of the worm. The relative

number of capilliform setae and palmate setae per bundle is

extremely variable. Some individuals have setae of the two

kinds in equal numbers, while others having a relatively large

number of capilliform setae have only one to three palmate

sette per bundle. Ventral sette, usually two in each bundle,

are present in all the somites except the first, eleventh, and

last. They are sigmoid, uncinate, and slightly enlarged at a

distance from the distal end about equal to one third the

length of the setae. The ventral seta- of the anterior region

are longer and less strongly curved than those of the posterior

part of the body (PI. XXXIX., Fig. 2, a, b).

There is no well-developed clitellum on any of the speci-

mens in our collection, none of which seem to be at the

height of sexual activity, but in a few individuals the



454 Illinois State Laboratory of Natural History.

hypodermis of XI is slightly modified. The prostomium and

anterior somite are very sensitive and thin-walled, and at the

slightest irritation are so retracted that the first setigerous

somite seems to form the end of the worm.

The brain is concave posteriorly, and its anterior part is

prolonged into a process on each side of the median line.

The alimentary tract has no special features distinguishing it

from other Tahificidie. The pharynx occupies somite II and

part of III ; the wall of the dorsal side is somewhat thicker

than that of the ventral side ; the transition from the oesoph-

agus to the intestine is gradual; and chlorogogue cells

appear rather abruptly in the anterior part of VI. The inner

epithelium becomes like that of the intestine in the posterior

part of VI, while the diameter of the alimentary tract becomes

considerably enlarged in VII. Posterior to this somite there

is no great change in the diameter of the intestine or in the

character of its walls. The ccelomic corpuscles. are very few

in number and of irregular form.

The circulatory system cannot be studied in the living

specimens, and it has proved an especially difficult task to

work out its anatomy from sections. One pair of "hearts "

is present in VIII, and in one specimen examined there were

additional lateral vessels nearly as large in IX. The "hearts"

communicate with the dorsal vessel, and no traces of a

supra- or sub-intestinal vessel have been found. Anterior

and posterior to the region of the reproductive organs the

alimentary tract is invested by an extensive system of blood

sinuses connected by a median ventral sinus or vessel, which,

however, seems to have no direct connection with the ventral

vessel nor to have the relations of a sub-intestinal vessel.

Paired nephridia are present in VII-IX, wanting in X-XIII,

and begin again in XIV. The nephridiopores are in line with

the ventral setse and a short distance in front of them.

The reproductive organs are similar in structure and

arrangement to those of many other TuhiJicidoR. The testes,

sperm athecae, and spermiducal funnels are in X, and the

ovaries, sperm-ducts, and spermiducal glands in XI, on

which somite are the spermiducal pores. The sperm-duct



IlUnois OUgocJuetd. 455

is somewhat elongated and occasionally protrudes backward

into the sperm-sac as far as the posterior part of XII. The

diameter of that part of the duct nearest the funnel is very

small (.01mm.), and that of its lumen not over .003 mm.
The diameters of duct and lumen both gradually increase

as the spermiducal gland is approached, and the course of

the duct becomes more tortuous. That part of the duct to

which the spermiducal gland is attached is expanded into an

elongated chamber or "atrium" (PI. XXXIX., Fig. 3), of

which the diameter is about .05 mm., that of its lumen being

.025 mm. Between the spermiducal gland and the pore the

sperm-duct is about .03 mm. in diameter where smallest.

The duct terminates in a protrusible penis, which is destitute

of a chitinous sheath. The spermiducal pores are in line

with the ventral setae of adjacent somites, and also with that

row of papillte which is associated with the set?e. As before

stated, there are no ventral setae on XL There are two median

sperm-sacs, lying dorsad of the alimentary tract ; an anterior

one in IX, and a posterior one in XI-XIY. In some cases

the latter extends into XV.

One pair of spermathec^ is present in X, and in one of the

sectioned specimens there is an additional spermatheca

in the right side of IX, which is similar in every way to those

of X except that it is slightly smaller. In the specimens

examined none of the spermatheca; contained any traces of

spermatophores. The spermathecal duct is nearly uniform

in diameter, and its length is one and a half to two times as

great as the diameter of the sac. In each case observed the

sac appeared like a hollow sphere with a broad invagination

of one side, but whether or not this collapsed appearance is

the normal one has not been determined. There seems to be

no difiference in the character of the wall in the different parts

of the sac, and no glands have been found in connection with

the spermathecal duct. The male organs are well developed

in all the sectioned specimens studied, but the ovaries have

not contained large ova, nor have there been any traces of

ovisacs or oviducts. These specimens were collected in

October, and the height of sexual activity is probably attained

at some other time of the year.



466 Illinois State Lahordfory of Natural History.

The relation of the species under consideration to other

Tuhific'uke cannot be finally determined in the light of our

present knowledge of the anatomy of this species and of

nearly related forms. In the presence of prominent non-re-

tractile papillae it resembles Peloscolex, Spirosperina, Hemi-

tubifex, and Emholocephalus. It probably is closely allied to

Leidy's Peloscolex variegatus ('52, p. 124), but the meager
description of that form and the lack of type specimens make
it impossible to determine this point. The absence of a chiti-

nous sheath about the penis distinguishes it from Spirosperma

and Hemitubifex, but there, are no characters given in the

description of Emholocepludiis Randolph ('93, p. 472), which

exclude it from that genus. The description includes, however,

no account of the (nrculatory system in the anterior part of

the worm nor any statement as to the presence or absence of a

chitinous penis sheath. Sections of E. plicatns kindly sent

me by Dr. Randolpli furnish no evidence of the presence of

this sheath in that species, but as they include none of the first

eight somites it is impossible to compare the anatomy of the

circulatory systems of the two species in that region. In

view of the above facts I have included the Illinois species in

the genus Emholocephalus, giving it the species name multi-

setosus. It differs from E. velutinus in having two kinds of

dorsal setse ; and from E. plicatns in having palmate setae

in the dorsal bundles, and in other particulars as follows :

(1) Inplicatus the dorsal bundles are said to contain usually

but six capilliform setse and three uncinate ones, and no state-

ment is made to indicate that there is any considerable vari-

ability in the number in different regions of the body. In

multisetosus, however, the dorsal bundles of the anterior region

each contain from eight to sixteen setae, while in the middle of

the body the number is much smaller, and the posterior somites

usually have no dorsal setae whatever. (2) The papillae of

plicatns are in two rows, equally distant from the septa,while in

multisetosus one row is in the plane of the setae and the other in

the plane of the septa. The papillae of multisetosus are also

much larger and more conspicuous than those of plicatns.

(3) The diameter of the lumen of the sperm-duct oi pUcatus is

nearly uniform throughout, while that of multisetosus is several

times greater in the region of the atrium than elsewhere.

Urbana, 111., Jan. 25, 1900.



Illinois OlujocJueta. 457

LITERATURE CITED.

Beddard, F. E.

'95. A Monograph of the Order of Oligocha'ta. 769 pp , 5 pis.

Benham, W. B.

'93. Note on a New Species of the Genera Nais. Quart. Journ. Micr.

Sci., Vol. XXXIV., pp. 383-386, PI. XXXIIl.

Oarman, H.

'88. On the Anatomy and Histology of a New Earthworm (Diplocar-

dia communis, gen. et sp. nov.). Bull. 111. State Lab. Nat. Hist., Vol.

III., Art. IV., pp. 45-77, PI. I.-V.

Goodrich, E. S.

'95. On the Structure of Vermiculus pilosus. Quart. Journ. Micr.

Sci., Vol. XXXVII., Pt. 3, pp. 253-267, PI. XXVI.-XXVIII.

Hatai, S.

'98. On Vermiculus limosus, a New Species of Aquatic Oligochaeta.

Annot. Zool. Japon., Vol. II., P. IV., pp. 103-111. 5 fig.

Leidy, J.

'52. Description of two New Genera of Vermes. Proc. Acad. Nat.

Sci. Phila., Vol. V., pp. 124-126.

'52a. Corrections and Additions to former Papers on llelminthology.

Proc. Acad. Nat. Sci. Phila , Vol. V., pp. 284-290.

Randolph, H.

'93. Beitrag zur Kenntnis der Tubiflciden. Jena. Zeitschr. f. Natur

wiss., Bd. XXVI., pp. 463-476, Taf. XVII.-XIX.

Smith, F.

'96. Notes on Species of North American Oligochaeta. II. Bull. 111.,

Statf Lab. Nat. Hist., Vol. IV., Art. XIV., pp. 396-413, PI. XXXV.-
XXXVIII.

stole, A.

'88. Monografie Ceskych Tubificidu. Morfologicka a Systematicka

Studie. Abh. Bohm. Ges. (2) VII., pp. 1-45, Tab. I.-IV.



458 Illinois State Laboratory of Natural History.

EXPLANATION OF PLATES.

ABBREVIATIONS.

at., atrium. n. c, nerve cord.

clit., clitellum. pr. spermiducal gland.

cobL, ccploin. p. V. I. v., posterior ventral lateral

vessel.

d. I. v., dorsal lateral vessel. sep., septum.

d. v., dorsal vessel. sp. ch., spermiducal chamber.

0. p., genital papilla. sp. d., sperm-duct.

g. s., genital seta. sp. th.., spermatheca.

g. s. gl
, gland of genital seta. sp. s., sperm-sac.

/. v., lateral vessel. v. n., integumental vascular
network.

m., muscles. v. v., ventral vessel,

m. 1'. I. v., median ventral lateral vessel, (^po., spermiducal pore.

Plate XXXIX.

Eniholocephalus multisetosus.

Fig. 1. Anterior part. X 18.

Fig. 2. Seta, x 250.

a and b, from ventral bundles.

c, palmate seta from dorsal bundle.

d, distal end of same.

Fig. 3. Sections of sperm-duct. X 180.

Rhizodrilus lacteus.

Fig. 4. Seise. X 250.

a, ordinary uncinate seta.

b, genital seta from IX.

c, genital setse from XI.

Fig. 5. Transverse section through spermiducal chamber. X TO.

Plate XL.

Rhizodrilus lacteus.

Fig. 6. Sagittal section through genital papilla, seta, and gland of IX.,

combined from several sections. X 180.

Fig. 7. Transverse section through spermathecae. X TO.

Fig. 8. Diagram of blood-vessels in VII-IX. _

Ilyodrilus coccineus.

Fig. 9. Diagram of blood-vessels in V-VIII., adapted from a figure by

Stole.

Vermiculus pilosus.

Fig. 10. Diagram of blood-vessels in IV-VI, from a figure by Goodrich.

Those of VII-X are similar.



Plate XXXIX.

i' f i<^ f/}

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sp.od.

?^j?
-^»;#'

3

/ /i'eoel-

sp.

\i(^\k-
uv. ,-/

5



Plate XL.

*N
-yy^-r:.. DC X

\ --' \ -->,.' ^^^«>,> y~- -\.*

^

V ' ':*? ''.. >.^,„v

"l.V. l.U.

'*rtSI