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Marroulaistants ii aay sts eri hiat asta Tatts tae tesst sets Perey. popsaaereege aratospenstetts ~e eas ye Sale ant Meeheatartats oo Seay rorbrenanaagedeynhrans eter dme erestseh t Sosqrecosaeayqcasee nortemnn te? Pennncrinetroanoi renin pateemmnataneneh tte ate nheatpetih Awd GoLsalbnas pin % Shit apart Tua olga ah eit arms an Guard TOR A erected: ne vy cang pene Decry ets ari ty iiBedebeh “mips Wen RSS eds Sikes we arereannespnianate saya etiy Apsara eT italien ena seine ssatdgsiicenveurnbert Witter moncecrety psumataatitiattcitemetgunemens tees brunet ‘ Hel das ts hkps Phe eens snergneubeasess Wine Reaches uirairlsnitellyolatvutpen tigre teas aetna ener anrenrelen netmmetesebeaee ee taepylacie tall tissepes , : inane echagegronprgcosbyosauiemtgrerPuaeataeg qangbenrneTsges Pate Peaatt by iriicentnt Sana doo tai net Omtutar ct eaanattaariet SES pronitraeare asinenmnareysraee aaieatpeaniatala “HISTORY Return this boox on or before the Latest Date stamped below. A charge is made on all overdue books. University of Illinois Library ILLINOIS BIOLOGICAL MONOGRAPHS VoLuME XVII PUBLISHED BY THE UNIVERSITY OF ILLINOIS URBANA, ILLINOIS 138 ILLINOIS BIOLOGICAL MONOGRAPHS veronicae (Lib.) Arn., Dimerosporium exc. 37-20 veronicae Lib., Dothidea exc. 37-20 veronicae Desm., Asteroma 37-20 veronicarum Rahb., Asteroma 37-20 verrucolosa Syd., Asterella 40-16 versi-color (Desm.) Theiss., Calothyrium versi-color (Desm.) v. Hohn., Microthyrium exc. 30-11 versi-color Desm., Sacidium exc. 30-11 versipoda Ryan, Asterina 37-135 vile Syd., Calothyrium 30-13 villaresiae Syd., Pycnoderma 24-3 violae Henn., Asterina 37-170 virescens Speg., Microthyrium 6-19 vitteforme Speg., Microthyrium 6-21 ae (Rehm) v. Hohn., Lembosia vriesiae Rehm, Micropeltis exc. 55-20 warscewicziae Henn., Lembosia 55-41 whetzelii Toro, Morenoella 56-19 winteriana (Pass.) Arn., Prillieuxina winteriana (Pass.) Theiss., Asterinella exc. 43-23 wintertana Pass., Asterina exc. 43-23 qwoodiana Doidge, Asterinella exc. 43-14 woodiana (Doidge) Ryan, Prillieuxina 43-14 wrightiae Syd., Asterina 37-194 wrightii (B. and C.) Theiss., Calothyrum 30-21 wrightit B. and C., Asterina exc. 30-21 xenospila Syd., Echidnodes 57-15 xylogenum Bomm., Rouss., and Sacc., Microthyrium 6-15 xylopiae (Henn.) v. Hohn., Phragmothyrium 14-15 xylopiae Henn., Micropeltis exc. 14-15 xylosmae Mendoza, Asterina 37-116 yerbae Speg., Myiocopron 1-19 zizyphiae Yates, Asterina 37-7 ILLINOIS BIOLOGICAL MONOGRAPHS Vol. XVII No. 3 PUBLISHED BY THE UNIVERSITY OF ILLINOIS UNDER THE AUSPICES OF THE GRADUATE SCHOOL Urpana, ILLINOIS EDITORIAL COMMITTEE Joun THEopore BucHHoiz FreD WILBUR TANNER Hartey Jones VAN CLEAVE UNIVERSITY 1000—2-40—17969 OF ILLINOIS 1 PRESS tr THE BRANCHIOBDELLIDAE (OLIGOCHAETA) OF NORTH AMERICAN CRAY FISHES WITH THREE PLATES BY, CLARENCE JAMES GOODNIGHT CONTRIBUTION FROM THE ZOOLOGICAL LABORATORY OF THE UNIVERSITY OF ILLINOIS No. 537 THE UNIVERSITY OF ILLINOIS PRESS URBANA 1940 CONTENTS I. INTRODUCTION II. ACKNOWLEDGMENTS . III]. Materrats AND METHODS OF STUDY . IV. History OF INVESTIGATIONS ON THE BRANCHIOBDELLIDAE V. MorPHOLOGY OF THE BRANCHIOBDELLIDAE . A. External Characters B. Body Wall . C. Digestive System . D. Vascular System E. Respiratory System F. Excretory System . G. Nervous System H. Reproductive System . VI. RELATIONSHIPS OF THE BRANCHIOBDELLIDAE VIT. CHARACTERS OF TAXONOMIC SIGNIFICANCE . Body Shape . Dorsal Appendages . Peristomium Jaws . Position of Caudal Cael . Shape of Gut . Pharyngeal Diverticula ; . Opening of the Anterior Newheidis : . Number of Testes . . Accessory Sperm Tube . Penis . Shape of Saraheee. Sig wee sus TIT. CLASSIFICATION OF THE AMERICAN BRANCHIOBDELLIDAE . Subfamily Branchiobdellinae new subfamily Genus Branchiobdella Odier, 1823 . Branchiobdella tetradonta Pierantoni, 1906 P Branchiobdella americana Pierantoni, 1912 . Subfamily Cambarincolinae new subfamily Genus Cambarincola Ellis, 1912 Subgenus Cambarincola new subgenus Cambarincola (Cambarincola) macrodonta Ellis, 1912 Cambarincola (Cambarincola) vitrea Ellis, 1919 Cambarincola (Cambarincola) elevata new species . Cambarincola (Cambarincola) inversa Ellis, 1919 . f— A pk pk a od CmoonnPPnnwmw © wON 24 DnanAumMmN VIII. CLassiFICATION (continued )— Subgenus Coronata new subgenus . . Cambarincola (Coronata) chirocephala Ellis, 1919 , weit aa (Coronata) ciel base ay: 1851 ae Cambarincola éhadai Vamasachi, 1933, sp. rine Genus Xironogiton Ellis, 1919 : Xironogiton occidentalis Ellis, 1919 . Xironogiton instabilius instabtlius (Moore, 1894) : Xironogiton instabilius oregonensis Ellis, 1919 . Genus Xironodrilus Ellis, 1919 Xironodrilus formosus Ellis, 1919 ; Xironodrilus pulcherrimus (Moore, 1894) . Xironodrilus pulcherrimus ET: (Moore, 1894) . .. Nironodrilus pulcherrimus Denials new subspecies... . Genus Bdellodrilus Moore, 1895 ae Bdellodrilus illuminatus (Moore, 1894) . Genus Stephanodrilus Pierantoni, 1906 . Stephanodrilus obscurus new species . Genus Triannulata new genus . : Triannulata magna new species . Triannulata montana new species Genus Pterodrilus Moore, 1895 Pterodrilus alcicornus Moore, 1895 Pterodrilus distichus Moore, 1895 Pterodrilus durbini Ellis, 1919 Pterodrilus mexicanus Ellis, 1919 Genus Cirrodrilus Pierantoni, 1905 Cirrodrilus thysanosomus (Hall, 1914) Nomina nuda IX. BroLoGy Host Specificity Food Habits Longitudinal Distribution of Branchiobdellids i ina ‘Stream X. CONCLUSIONS . BIBLIOGRAPHY PLATES I. INTRODUCTION THE BRANCHIOBDELLIDAE comprise a family of annelid worms which live on the bodies of crayfish. In the older literature this family has been designated as the Discodrilidae, but Hall (1914) showed this name to be untenable as there is no genus Discodrilus. This family is known from Europe, eastern Asia and Japan, and North and South America. So far as is known, these worms are always found on crayfish, but the question whether or not they are parasitic in their food habits is far from settled. The writer believes and will attempt to show that their food consists largely of diatoms and that they are for the most part non-parasitic. The descriptions of the American branchiobdellids are scattered throughout a number of papers published in various sources, some of which are not generally available. The last paper dealing with the taxonomy of the American forms (Ellis, 1919) appeared twenty years ago. Inno recent paper has there been any attempt at synthesis of all the described species by means of diagnostic keys. The last attempt at such synthesis was by Hall in 1914, but his material was so meager that his keys are inadequate, and over half the species now known were described after his paper was published. Except for a new species, inadequately described from poorly preserved material, he included no specific descrip- tions or comparisons. Of the known species the locality records are from only a few well- known areas, and many are known from the type locality only. Thus the geographical limits of the species are poorly defined. The last important paper was by Ellis in 1919. He described in fine detail a number of new species and gave new locality records for a few old ones, but he presented few dignostic keys and attempted very little synthesis. The present study summarizes the existing information on American forms, presents diagnostic keys, further defines the range of the species, and adds four new forms which were encountered. In an attempt to evaluate the taxonomic importance of morphological characters, the family is divided into two natural groups, the forms with two pairs of testes being recognized as the basis for a new subfamily (Cambarinco- linae). The present study also adds to the existing knowledge of the biology of the family. Il. ACKNOWLEDGMENTS THE WRITER wishes to express his sincere appreciation for the help given him by Professor H. J. Van Cleave, of the University of Illinois. under whose direction this investigation has been conducted. Throughout the NI 8 ILLINOIS BIOLOGICAL MONOGRAPHS entire period of study Professor Van Cleave has given helpful advice and encouragement, thus contributing largely to whatever success this investigation has attained. The writer is indebted to Dr. Carl L. Hubbs for permission to examine the material in the Museum of Zoology, University of Michigan, and for a place to work while at the museum. He also wishes to express his thanks to Dr. David H. Thompson for permission to examine the material in the collections of the Hlinois State Natural History Survey, to Dr. Percy Moore for advice and criticism, to Dr. A. S. Pearse for material from North Carolina, to Dr. John D. Mizelle for specimens from Oklahoma, to Dr. James Sanders for specimens from South Dakota, to Dr. J. Henry Walker for material from Alabama and Florida, and to Dr. Edwin P. Creaser for information concerning the location of collections. The writer is likewise indebted to his fellow graduate students, especially Dr. Harry G. Kimpel, for assistance in making field collections. Ill. MATERIALS AND METHODS OF STUDY LARGE AMOUNTS of material were available for this study. In general, two methods were employed to obtain this material: (1) actual collecting of crayfish and removing of worms, and (2) examining museum jars of preserved crayfish and obtaining the worms that had fallen to the bottom or still remained on the dead crayfish. For fixing the worms, the best results were obtained with warm A.F.A. (85 parts 85% alcohol, 10 parts formalin, 5 parts glacial acetic acid). The crayfish were dropped into this solution and the fixed worms were gathered from the bottom after decanting. However, the worms fixed in formalin and higher grades of alcohol were found to be adequate for taxonomic studies, though slightly contracted. Worms were studied both from total mounts and from sectioned material. The best results with total mounts were obtained by running the worms up through the grades of alcohol and clearing in xylol, then mounting in balsam without staining. In some cases excellent results were also obtained by staining with a solution of four drops of Delafield’s hematoxylin and four drops of Ehrlich’s acid hematoxylin in 20 cc. of a saturated water solution of potassium alum, then destaining, neutralizing in running tap water, clear- ing, and mounting in balsam. Borax carmine was also used with some success. While in most cases the significant taxonomic details could be demonstrated in total mounts by means of dorsal, ventral, and lateral views, these findings were checked by means of sections cut at 10 or 20 microns. Transverse, frontal, and longitudinal series were prepared. BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 9 Excellent results were obtained by staining the sections with Delatield’s hematoxylin, going up through alcohols to 70%, destaining in acid 70%, running down to water, and washing in tap water 30 minutes or longer, going up to 95% alcohol, counterstaining with eosin, clearing, and mount- ing in balsam. Heidenhain’s iron hematoxylin, with eosin as a counter- stain, was used to some extent. The paraffin ribbon was affixed to the slide with bakelite. A mixture of 2.0 grams gelatin, 1.0 grams phenol, 15 cc. glycerin, and 100 cc. dis- tilled water was smeared on the slide, and the sections were floated on with 4% formaldehyde solution. Of the twenty-two species included in this study, all but three have been studied from large amounts of material, many species being repre- sented by hundreds of specimens. Field observations were also carried on during this study to determine the abundance and distribution of the branchiobdellids. IV. HISTORY OF INVESTIGATIONS ON THE BRANCHIOBDELLIDAE APPARENTLY the first published note of this group was by Rosell (1755). Braun in 1805 mentioned them in a description of some leeches. A few other papers, Miiller (1806) and Savigny (1809), mention them also, but it was not until 1823 that the first taxonomic description was given. In that year Odier published in the Mémoires de la Société d’Histoire Naturelle de Paris a very fine description of the common branchiobdellid of western Europe which he called Brancliobdella Astact. He believed it was a leech and closely related to the genus Hirudo. He gives (p. 75) the following characterization of the genus: “un corp contractile un peu aplati, composé de dix-sept anneaux, terminé par un disque préhensile; une téte oblongue, garnie de deux lévres; une bouche armée de deux machoues cornées, triangulaires, dont la superieure plus grande, et point d’yeux.”” He spends some time (p. 76) pointing out that this form was a leech and not a tipulid larva as one M. de Blainville had previously reported to the society. Apparently no important work was published on the group for the next twenty years. Then in 1835 G. Henle reported a careful anatomical study in an article entitled “Ueber die Gattung Branchiobdella.”’ Vallot in two papers (1839 and 1845) also reported briefly on this group. Moquin-Tandon in his leech monograph of 1846 included a description of Branchiobdella. Previous to 1851 all work on this family was by Europeans and on European species, but in that year Joseph Leidy published in the Pro- ceedings of the Academy of Natural Sciences of Philadelphia (p. 209) a 10 ILLINOIS BIOLOGICAL MONOGRAPHS description of an American species which he called Astacobdella phila- delphica. There followed a series of brief papers by Europeans on branchiobdellid anatomy, but thirty-one years elapsed before the next significant taxonomic paper was published. The next American paper was by Verrill (1873). In his synopsis of American leeches he republished Leidy’s description of 1851. A series of papers published in Europe on European species next appeared. Whitman (1882) published a description of Branchiobdella pentadonta, a new species. Next appeared a number of papers on the anatomy and development of Branchiobdella. These were by various Europeans who were only incidentally interested in the group. These included Gruber, Lemoine, Voigt, Ostroumoff, Vejdowski, Rohde, Salensky, and others. In 1894, forty-three years after Leidy’s paper, Moore published descriptions of “Some Leech-like Parasites of American Crayfish.” He included Branchiobdella illuminata, B. pulcherrima, B. imstabilis new species, and B. philadelphica (Leidy) in his discussion. The following year, in another paper, he described a new genus, Pterodrilus, which included two new species, P. alcicornis and P. distichus. In 1895 Moore published a very fine account of the anatomy of Bdellodrilus illuminatus (Moore). This is the best general anatomical account yet published and the only one on an American species. He pointed out in this paper the need for more work on the nephridial system. This complicated system was worked out and the results were published the following year by Voinow on Branchiobdella varians. Moore in 1897 gave an excellent account of the nephridial system of Bdellodrilus Wlwminatus. Four years later, 1901, his monograph on the leeches of Hlinois was published in which he mentioned the fact that in the collection Bdellodrilus phila- delplica was found on Cambarus diogenes and C. blandingi. This paper marks the end of Moore’s work on Branchiobdellidae. Afterwards he turned his attention largely to leeches. F. Schmidt pointed out in his papers (1902 and 1903) that the musculature was more definitely similar to the Oligochaeta than to the Hirudinea. Some time later (1905) Pierantoni, an Italian, began to publish on the group, giving a description of Cirrodrilus cirratus, a new species from Japan. He followed this in 1906 by a brief general account of the genus Branchiobdella. In another paper (1906b) he described two new forms, Branchiobdella tetradonta from California and B. digitata from Japan. In the same year Smallwood, an American, gave an account of some observations on the life habits of some branchiobdellids in the neighborhood of Clear Lake, New York. The year 1912 is a memorable one in the study of this group, for BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 11 in that year Pierantoni published the first monograph. In this he sum- marized the anatomy of branchiobdellids and showed that they are definitely Oligochaeta. He included several new species and all previous ones. He listed: Cirrodrilus cirratus Pier. from Japan, Branchiobdella parasita Henle, B. pentadonta Whitman, B. hexadonta Gruber, and B. astaci Odier from Europe; B. minuta n. sp. from Amur-Riff ; B. anatis n. sp. and B. dubia n. sp. of unknown habitat; Stephenodrilus sapporensis Pier., S. japonicus n. sp. from Japan; S. koreanus n. sp. from Korea. From America he listed Branchiobdella tetradonta Pier., B. americana n. sp., Bdellodrilus pulcherrimus (Moore), B. instabilus (Moore), B. idluminatus (Moore), B. philadelphicus (Leidy), Pterodrilus alcicornus Moore, and P. distichus Moore. In the same year (1912) Ellis described a new American worm, Cambarincola macrodonta from Colorado. He included a brief key to some of the described forms. Two years later (1914) Hall briefly and inadequately described a new species from Utah which he called Cera- todrilus thysanosomus. He also included a summary of locality records for American species and erected the superfamily Branchiobdelloidea. In 1915 Tannreuther published a cell lineage study using Cambarincola philadelphica as a subject. In 1918 Frank Smith included a few species in his chapter in Ward and Whipple’s ‘Fresh Water Biology.’”’ In the same year Ellis listed species he collected around Douglas Lake, Mich- igan. In 1919 he published an account of “The Branchiobdellid Worms in the Collection of the United States National Museum.” He described as new Xironodrilus formosus, Xironogiton occidentalis, Xironogiton oregonensis, Pterodrilus mexicanus, Pterodrilus durbini, Cambarincola vitrea, Cambarincola chirocephala, and Cambarincola inversa. This is the best single article on the taxonomy of the American species, but no generic keys and few specific keys are included. This was Ellis’ last paper on the branchiobdellids. In 1928 Alessandra gave an account of a new European species, Branchiobdella italica. Stephenson published a monograph on the Oligochaeta in 1930, in which he gave a lengthy discussion of the Branchiobdellidae, including as valid genera: Branchiobdella, Cirrodrilus, Stephanodrilus, Bdello- drilus, Pterodrilus, Ceratodrilus, Cambarincola, Xironodrilus, and Xiro- nogiton. In 1932 H. Yamaguchi began writing on this group. He pub- lished several preliminary papers and finally in 1934 a monograph of the Japanese forms including nineteen species in three genera. In 1935 Evans collected worms in Champaign County, Illinois. He reported (1939) four species: Cambarincola macrodonta, C. vitrea, C. chiro- cephala, and Bdellodrilus illuminatus. 12 ILLINOIS BIOLOGICAL MONOGRAPHS V. MORPHOLOGY OF THE BRANCHIOBDELLIDAE PrERANTONI (1912) in the first general monograph of the group charac- terizes the Branchiobdellidae as follows: Corpo diviso in due regioni, una cefalica di tre segmenti con lobo preorale ventosiforme, bilobo o plurilobato, con o senza appendici digitformi ed un/’altra regione, del tronco, di ll segmenti, terminata da ventosa e priva di setole. Bocca provvista di due forti mascelle pid: o meno dentate. Sistema circolatorio fatto da un vaso dorsale con seno perienterico e da un vaso ventral riunito a quello da quattro paia di tronchi trasversali anteriori e da uno posteriore. Sistema escretore fatto da due paia di nefridii posti nei segmenti del trunco aprentisi per pori dorsali posti nel 4°e nel 9° segmento del tronco. Testicoli 1 0 2 paia, nel 5°o nel 5°e nel 6° segmento del trunco. Spermateca nel 5° segmento, impari; atrio ugualmente impari provvisto di pene e di condotti seminali pari in numero di due o di quattro, con corrispondenti paia di imbuti ciliata nel seg. 5°e nel 6°, trattenuti dai sepimenti posteriori corrispondenti ; ovaril e pori femminili nel 7° segmento. A. EXTERNAL CHARACTERS The branchiobdellids are a homogeneous group of worms ranging from 1 to 12 mm. in length. The body consists of two parts, the head and the trunk. A caudal sucker is present at the posterior end of the body. The head is somewhat cylinder-shaped. The mouth is surrounded by fleshy lips, which may or may not be lobed. In some forms the lobes may be extended into tentacles. Inside the mouth, at the base of the muscular ring or sucker, is a circlet of numerous minute papillae. The head shows a groove at the base of the lips and a median dorsal depression. The lack ot definite segmentation has led to various interpretations of the number of annuli included. Pierantoni (1912) considered that the head consists of a prostomium and three segments; the prostomium represented by the peribuccal region, the first cephalic segment between the peribuccal ring and the dorsal pit, the second segment posterior to the pit, and the third, indistinct in most species, bordering the trunk region. According to Pierantoni there are three bilobed ganglia and three vascular commissures connecting dorsal and ventral vessels; so he concluded that the internal anatomy agreed with his three-segment theory. Moore (1895b:499) con- sidered the peribuccal ring as a segment and so believed there are four head segments. Schmidt (1905) agreed with Pierantoni that there are only three, while Vejdowski (1884:39) thought that there are six or seven segments, since the ganglia are bilobed. Ellis (1912:482) and Stephenson (1930:796) agree with Moore. Stephenson (1930:796-797) summarizes the evidence for the four-segment head theory as follows: It would, however, seem to be erroneous to describe the circumbuccal ring as a prostomium; it is obviously a peristomium, and the peristomium is universally the first true segment in the Oligochaeta. If so reckoned here, there would be BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 13 four segments in the head, the prostomium having disappeared (as, e.g., in Chaetogaster) as a distinct division. Moreover, in the Limicolae the first segment has no vascular commissures (apart from the arch uniting the anterior ends of the dorsal and ventral vessels) ; the first of the commissural vessels is in segment II. The vascular arrangement of the Branchiobdellidae, therefore, also indicates four segments to the head. Again F. Schmidt (1905) describes a thickening situated at the middle of the length of the pharyngeal connective on each side, which is due to an aggregation of nerve cells; a nerve is given off from the connective just above, and another from just below, this thickening, and these nerves pass forward to the buccal segment. The thickening is in addition to the buccal ganglion (with a visceral distribution), and seems to represent the proper ganglion of the buccal segment, so that again four cephalic segments seem to be indicated. Lastly, by counting four head segments the position of the genital apertures and organs is brought into line with that in the majority of genera of Lumbriculidae, with which the Branchiobdellidae are closely allied. My own observations tend to support the four-segment theory. The trunk region is variously shaped in different species. In some forms, as Cambarincola, it is cylindrical and relatively uniform in diameter throughout its entire length. In others as Xironodrilus, it is flattened and wider in segments VI and VII than in the others. Xironogi- ton is flattened and widest in the posterior segments. Dorsal appendages are present in some forms. In Pterodrilus these consist of cylindrical fleshy protruberances along the median dorsal line of the body. In Cirrodrilus they extend transversely across the dorsal surface as a pointed band with usually six, sometimes seven or eight, points on the free margin. These dorsal appendages usually have ridges of transverse muscle fibers associated with them. Little is known of their function. Moore (1895a:450) first pointed them out on American species. He says: Regarding the function of the dorsal organs there is little to say. A priori one would expect them to be respiratory, but the apparent entire absence of blood vessels, which are unrevealed after a careful study of sections would tend to throw strong doubt upon such an interpretation. Irregular spaces are evident here and there between the muscle fibres but these appear to be continuous with the inter- muscular spaces which are developed between the circular and longitudinal muscle fibres of the body walls, and have not been traced into any communication with the body cavity. Until an opportunity is afforded of studying living examples in their proper habitat, and observing the uses to which these organs are put, no opinion can be vouchsafed. Externally the trunk consists of eleven segments. The first eight are quite distinct and prominent. They are divided into two unequal parts by a sulcus towards the posterior fourth of the segment. The last three segments are smaller and less distinct. The last segments form the caudal sucker, the principal attachment organ of the worm. On a few species additional small, somewhat concave, glandular adhesive disks are present near the lateral margin of segments VIII and IX. This is true in Xironodrilus pulcherrimus (Moore) and Nironogiton occidentalis Ellis. Pierantoni (1912) says the internal segmentation would correspond 14 ILLINOIS BIOLOGICAL MONOGRAPHS to the external as there are nine ganglia on the trunk portion of the nerve cord and the most posterior of these corresponds to three. He shows this last by tracing the nerves that have their origin in the posterior ganglion. Schmidt (1905) thinks otherwise, believing the last ganglion cor- responds to five. This then would make the total number of trunk segments thirteen. My own observations on this point have been in no way conclusive but they tend to support Pierantoni’s view. B. Bopy WaLL The epidermis contains a great number of glands. Moore (1895b: 502) gives the best account of the epidermis and its glands in connection with his study of Bdellodrilus illuminatus: The epidermis consists of ordinary epithelial cells, of non-nucleated protoplasm, and of gland cells, which are present in great number and variety. The epidermis proper presents little modification. The cellular elements are arranged with rela- tion to the circular muscle fibers, which encircle the body walls at regular intervals and are so deeply imbedded in the epidermis that they are frequently almost in contact with the cuticle, only a thin layer of protoplasm separating them. Concerning the epidermal glands, Moore (1895b:503) continues: Glands are very richly developed in connection with the epidermis of B. Uluminatus; and while all are constructed of similar elements, they differ much in size and arrangements of these elements. The elements are unicellular glands somewhat of the goblet cell type. In most cases they consist of an enlarged irregularly polyhedral body containing the nucleus, and tapering at one end into a slender, more or less elongated ductule. The only exceptions are those glands which are referred to as salivary and bursal glands. Certain small mucous glands are very generally distributed over the skin; especially on the head, where they are regularly arranged in several transverse rows. They may be unicellular, or consist of three or four unicellular glands, the ductules of which are twisted or spiral. On the sixth and seventh somites such glands become greatly increased in number and size; the body walls, particularly on the dorsal side, being little more than a thick glandular layer, which constitutes the clitellum. The unicellular glands are here aggregated in sub-globular or pyriform groups of from three to twenty or more, which extend inward to a length of from .03 mm. to .065 mm. Being arranged in a single stratum each cell forms part of the surface of the gland, close to which lies the deeply staining nucleus, in a mass of almost as deeply staining glandular protoplasm. The inner ends are glandular but clear and often unstained, and pass into ductules, which may be bound together into a fascicle, and either open in close proximity on the surface, or separate and open singly. In either case they wind a slightly spiral course, which is best seen in living animals, particularly when stained with methylene blue. The cell bodies have an average diameter of .011 mm., the ductules of .0018 mm., and a total length of about .05 mm. The several cells in each group appear not to function simultaneously. Some have completely broken down into secretion while others are entirely protoplasmic. Other masses of gland cells are developed in different parts of the epidermis. This is true in connections with the head, lips, and especially the posterior sucker. Concerning this last Moore (1895b:504) adds: Glands similar to those described by Dorner, and more fully by Voigt, in Branchiobdella, are well developed in this species in relation to the posterior BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 15 sucker. The glandular masses, which largely fill the tenth and eleventh and part of the ninth somites, are pyriform, or aggregations of several pyriform groups. Large, granular, lightly staining cell bodies give rise to long slender ductules which, first united into fascicles, break up into smaller and smaller groups, and are finally distributed singly on all parts of the surface of the acetabulum. This arrangement is beautifully shown in living specimens. The ductules are filled with rounded granules, which may be forced from their mouths in living worms by pressure. The granules will emerge in strings, absorb water, swell, and run together in a very short time, forming a homogeneous mucus. The body wall is then made up of epidermis, with its cuticular cover- ing, and the muscle layers of circular and longitudinal muscle fibers. These muscle layers are arranged like those of most Oligochaeta with an outer circular and an inner longitudinal layer. According to Schmidt (1903), in Branchiobdella the cells of the circular layer regularly number twenty-five on each side of an ordinary segment; and each segment has its own system of longitudinal cells, forty-four in each half of the segment. The cuticle is thin, transparent, colorless, nearly homogeneous and follows the epidermis, which secretes it, closely. It follows invaginations into the oral and sexual cavities. Cuticular markings are evident and appear to be different in different species. It is possible that these mark- ings may furnish diagnostic characters. The writer hopes later to investigate this possibility. The intersegmental septa, according to Moore, are formed of thin sheets of parallel dorso-ventral muscles arising from the ends of the longitudinal fibers. Septa practically disappear between the first four segments and are represented by thin slips that support the alimentary tract from the body walls. Septa are extremely well developed between the sexual somites. The musculature of the posterior sucker is very well developed. Moore (1895b:509) says about Bdellodrilus illuminatus: The musculature of the posterior sucker is complex, and well adapted to secure strength and mobility. The circular muscles undergo little change; but the longitudinal split up, by the branching of individual fibers, into a set which are the direct continuation of the body longitudinal fibers, a second set which pass dorso-ventrally across the body cavity, a third which radiate to the margins of the disc, and lastly a highly branched set which have become slightly displaced at their posterior ends, right or left from their original longitudinal direction, and consequently pass with a slight spiral turn from the body walls to the periphery of the sucker, where they cross and interlace with their fellows having an opposite displacement. C. DIGESTIVE SYSTEM The alimentary canal may be divided into several regions, the oral, pharyngeal, esophageal, intestinal, and anal. The mouth is situated between the lips into which the peristomium is divided. Aggregations of unicellular glands are developed from the margins and inner surfaces of the lips. 16 ILLINOIS BIOLOGICAL MONOGRAPHS Posterior to these are slit-like dorsal and ventral infoldings of the epidermis and cuticle, bounded by a thickened epidermal pad. On the posterior walls of these invaginated pockets, the jaws are molded. These jaws, one ventral and one dorsal, are solid chitinous plates. According to Ellis (1919:242) the primitive type is one with several sub-equal teeth. Modifications have progressed along one or both of two lines, namely, (a) reduction in number and (b) increase in size of some teeth correlated with reduction in size of others. The jaws are provided with a powerful musculature. This is well described by Moore (1895b:511) for Bdellodrilus illuminatus: The mechanism of the jaws is seen to be powerful and efficient. The muscular plates, with their radiating fibers, regulate the distance between the two jaws, approximating or separating them as the circular or radial fibers contract in turn. The circular muscles seem sufficiently powerful to bring the jaws together with crushing force. The protractor muscles carry the jaws forward (with a rotary or rocking movement on the muscular pads) against an object of attack, the lower jaw acting with its teeth as a hook, while the powerful retractor muscles of the upper jaw bring its toothed blade with a shearing motion between the ventral teeth. Thus is constituted an efficient pruning apparatus, the chief purpose of which is, I believe, the clipping off of branchial filaments of the crayfish host, from which the blood is then drawn. They are probably also used for mowing down the colonial infusorians which cluster along the borders of the branchial chamber, and remains of which are frequently seen with diatoms, etc. mixed with crayfish blood in the stomach of the worms examined. The jaws mark the beginning of the pharyngeal region, which is characterized by great development of the musculature and which may function as a suction bulb. This region extends to the esophagus, which usually begins in the first body segment. The esophagus is short and ill-defined. Its muscular coat is made of a sheet of circular and longitudinal muscles. This coat continues through- out the intestine, into which the esophagus rapidly merges. The intestine continues with various sacculations to the anus, situated in the dorsal half of segment X. In the second or third somite the peritoneum is modified to form chlorogogue cells which envelop the intestine except in the seventh somite. In the region of the dorsal blood vessel they arch over its walls. According to Moore (1895:513) they appear in surface view as “a mosaic of large polygonal cells, with straight closely fitted edges, possessing a large clear nucleus, and cytoplasm of a greenish brown color, due to the presence of numerous large granules and minute globules. In sections they appear more or less flattened, or prominently bulging, according to their position and the degree of contraction of the intestine.” Being absent in the seventh segment they permit the maturing ova to come into close contact with the walls of the blood sinus, an important nutritive consideration. The intestine in segments VIII and IX is a very narrow tube, the rectum. In the region of the anus the circular muscles increase to form a sphincter. BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 17 D. THE VascULAR SYSTEM According to Stephenson (1930:798) the vascular system of the Branchiobdellidae consists of a peri-enteric sinus, a dorsal and a ventral blood vessel, four pairs (three cephalic and one in front of the trunk) of vascular commissures in the anterior part of the body and one near the posterior end. Moore (1895b:514) found seven vascular arches present in Bdellodrilus illuminatus; four in the head and one each in segments I, VII, and IX. These connect the dorsal and ventral blood vessels. In front of the third segment the dorsal! vessel is large and pulsatile (the so-called heart) but posterior to this it loses its distinct identity and merges into the peri-enteric sinus. Moore (1895b:51+) describes this sinus as follows: The peri-enteric blood sinus, to which Voigt first especially called attention in Branchiobdella, is highly developed in the present species, in which it exists as a continuous space between the muscular and epithelial coats of the intestine, extending from the third to the eighth somites inclusive, and breaking up at each end into a system of passages and lacunae having a retiform arrangement. The sinus has an average depth of .005 mm., and is without true walls other than the intestinal coats between which it lies. It is crossed by numerous protoplasmic strands and columns which bind its walls together, and remind one of the stalactites and columns of a limestone cave. These become larger and more frequent towards the ends of the sinus, which they finally interrupt so much as to convert it into the terminal plexuses mentioned. Throughout its entire length the ventral blood vessel lies in contact with the dorsal side of the nerve cord and passes through the ganglia of each segment in a deep groove. The ventral vessel terminates in the tenth segment in a pair of large trunks which arch around the intestine, and pass forward to empty into the dorsal region of the peri-enteric sinus, thus forming the beginning of the dorsal enlargement, which here receives the dorsal ends oi the plexus of the blood passages. Concerning the connecting lateral arches in Bdellodrilus, Moore (1895b:516) continues: In the seventh somite it [the ventral blood vessel] gives off a pair of large ovarian vascular arches, which empty into the dorsal enlargement of the peri- enteric sinus. The supra-neural vessel terminates in the tenth somite in a pair of large trunks, which arch around the intestine, and pass forward to empty into the dorsal region of the peri-enteric sinus, thus forming the beginning of the dorsal enlargement, which here receives the dorsal ends of the plexus of blood passages. Of the seven pairs of lateral arches mentioned, a labial and three cephalic pairs, in the pharyngeal region, arise from the anterior prolongation of the heart; an oesophageal pair which owing to their great length are often looped into the succeeding somite, arise from the anterior end of the heart itself; a large pair of ovarian arches, which are more or less imbedded in the maturing ova, lie in the posterior part of the seventh somite; and the seventh pair, the largest of all, posteriorly connect the supra-neural vessel with the peri-enteric sinus. The walls of the supra-neural and lateral vessels are very delicate and non-contractile. At wide intervals, nuclei, which resemble those of the peritoneal cells, may be detected, but I have found no traces of cell boundaries. ILLINOIS BIOLOGICAL MONOGRAPHS mn ~ E. Resprratory SYSTEM In the Branchiobdellidae, as in many aquatic Oligochaeta, there are no specialized organs of respiration. Respiratory exchange simply takes place in general through the body wall. F. Excretory SYSTEM The excretory system of the group consists of two pairs of nephridia. Those of the anterior pair are placed asymmetrically and open in the dorsal part of segment III just behind septum II/III. They may open either through a single pore or through paired pores. As mentioned, they are not symmetrical, so the one may extend from segment III to I, and the other posteriorly from II] to [V. The nephridia of the posterior pair are symmetrical and situated in segment VIII, opening to the outside just behind furrow VIII/IX. The best accounts of the finer anatomy of the branchiobdellid nephri- dium are furnished by Moore (1897) and by Voinow (1896). These studies are well summarized by Stephenson (1930:224-226), who says: Each nephridium begins in an open ciliated funnel, of which the lips are formed of two marginal cells; the single central cell bears a long ciliary flame, and unlike that of Lumbricus is tubular and surrounds the whole funnel below the marginal cells; this is followed by the stalk of the funnel, also composed of a single cell. The next region constitutes the special peculiarity of the Branchiobdellid nephridium; it is called by Moore the plexus region. In the undisturbed condition of the organ it forms a compact lobulated mass; but when this is slightly teased apart it is seen to consist of a single tube, alternately swollen out and contracted; in each swelling there is a labyrinth of branching and anastomosing canals, while in each contracted part the lumen is single. At each contracted part is a nucleus, and here also on the inner surface of the wall is a ciliary flame; both nuclei and flames are absent from the parts occupied by the plexuses. The tube is to be considered as intracellular, the territory of each cell consisting of one of the narrowed sections of the tube and the adjacent parts of the swellings on each side. The plexus region is granular and yellowish and appears to be a seat of considerable excretory activity. The looped portion of the organ succeeds the plexus region. It consists of two loops, a longer and a shorter, the longer with an irregular and twisted course, the shorter less tortuous. Each limb consists of a series of drainpipe cells, and the two limbs of a loop are apposed and mostly fused together. In the long loop are seen at intervals nuclei and accompanying ciliary flames—twelve of each; in the connecting tube between the two loops is a single nucleus and flame, and in the short loop ten nuclei but only one flame. On the inner surface of the tube in this region are seen peculiar minute rod-like markings, most numerous at the turning-point of the long tubule; these are occasioned by a lining coat of bacteria. The wall of the long loop is only slightly granular, that of the short stains deeply and is very densely granular, the granules being disposed in radial lines. In the walls of the short tube, in the living organ, are seen granules exactly similar to others contained within the enlarged peritoneal cells which invest the loops, and similar granules occur also in its lumen. The cells, therefore, deposit solid particles in the lumen of the tube, in addition to passing in fluids containing matters in solution. Accumulations of disintegrated coelomic corpuscles are stated by Moore to be found in all parts of the nephridial lumen. BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 19 The duct passes along the plexus region, the zigzags of which are arranged on it as on a supporting axis, then surrounds the neck of the funnel in a small loop, undergoes a thickening of the wall in which are several small diverticula of the lumen, and enters the body wall. It consists of about ten cells, but no cilia. The peritoneal covering is constituted by large cells with elongated processes extending outwards into the coelomic cavity. These cells apparently also take part in the excretory process. G. Tue Nervous SYSTEM The branchiobdellids have a pair of supra-esophageal ganglia lying just posterior to the dorsal jaw pad. According to Moore the two ganglia are united across the median line by a cord of nerve cells and a fibrous commissure. Each bears posterior lobes which are in turn divided into large external and small internal parts and connected to the main ganglion by three strands of nervous tissue. The circum-esophageal connectives extend as thick strands of nerve fibers with a partial covering of nerve cells from the ganglia. They pass around the pharynx and each bears a bilobed stalked ganglion just before they join. They unite to form the ventral nerve cord, and just posterior to this anastomosis form two pairs of larger ganglia. This makes four pairs of double ganglia within the limits of the head (see four-segment head theory above). Numerous nerve fibers arise from the circum-esophageal connectives and the supra-esophageal ganglion and pass forward to the peristomial region. These end in the circum-oral hairs and oral papillae. The ventral nerve cord consists of two distinct halves throughout its length. It enlarges at the ganglia and narrows in the inter-gangliar intervals. In the body segments there are eight pairs of bilobed ganglia and a posterior ganglionic mass called the anal ganglion. This ganglion is com- posed of several pairs of ganglia, three according to Moore and five according to Schmidt. The fifth and sixth ganglia are displaced to the right of the median line by the spermatheca and male atrium. Three pairs of nerves arise from the region of each pair of ganglia, one from each end and one from the transverse constriction. They supply the body walls, going between the two layers of muscles and splitting up as they proceed. The first and second nerves supply the major annulus; the third splits, one branch going also to the major annulus, the other branch supplying the minor annulus. A thin muscular sheath encloses the nerve cord for its entire length and includes the ventral blood vessel. H. THe REPRODUCTIVE SYSTEM The male organs are situated in segments V and VI. In the genus Branchiobdella a pair of testes is present in segment V. In all other known genera an additional pair is present in segment VI. The sperms 20 ILLINOIS BIOLOGICAL MONOGRAPHS are liberated directly into the body cavity, and in mature worms the testes cannot be detected. One or two pairs of vasa deferentia and funnels (depending on the number of testes) are present. The two vasa defer- entia of each pair unite and all open within a single atrium. The atrium consists of a dilated ental portion and an ectal portion that is a narrow short bursa. The penis, which may or may not be eversible, is situated within the bursa. According to Michaelson, the atrium may be provided with glands near the place of entry of the vasa deferentia, but these are never compacted into a single prostate. In some genera an accessory sperm tube is present. This consists of a blind tube extending dorsally and anteriorly from the bursa. The female reproductive system is situated in segment VII. A pair of ovaries is situated on the posterior face of septum VI/VII. In sexu- ally mature worms large eggs are often present in segment VII. The oviducts are represented by two funnel-like pores in the ventro-lateral walls in the posterior part of segment VII. These pores are ciliated. A glandular clitellum forms about these genital segments. A spermatheca is present in segment V. It is unpaired and opens in the mid-ventral line about the middle of the segment. It is quite variable in form in different species. The blind end is usually free but may be attached by means of a peritoneal investment. VI. RELATIONSHIPS OF THE BRANCHIOBDELLIDAE From their general appearance, the presence of jaws, the absence of setae, and the posterior sucker, the Branchiobdellidae were originally con- sidered leeches. Odier (1823) in the first taxonomic description of the group has a sub-title of “Nouvenu Genere d’Annelides de la Famille des Hirudinées.”” Leidy (1851) and Verrill (1873) considered the American branchiobdeilids to be leeches. They were omitted by Beddard (1895) in his monograph on the Oligochaeta, and Michaelsen (1900) failed to include them in his monograph in the Tierreich series. Later Michaelsen (1919b) insisted that they were Oligochaeta and closely related to the Lumbriculidae. In 1903 F. Schmidt showed that the musculature in the Branchiob- dellidae is definitely like that of the Oligochaeta and unlike that in most Hirudinea. Pierantoni (1912) in his monograph discussing their anatomy as Oligochaeta notes how closely they resemble Mesoporodrilus. Michael- sen (1919b) shows how the peculiar characters of the branchiobdellids are merely adaptations to parasitic life and could be derived from other Oligo- chaeta. The short body and posterior sucker are apparently adaptations to the habitat. The pharynx, he says, is a sucking apparatus, and the prosto- mium is absent. Both these characters are present in Chaetogaster, a BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 21 genus of Naididae the members of which are carnivorous and sometimes ectoparasitic. Michaelsen further compares the jaws to the pair of buccal stylets with chitinous tips in the buccal cavity of certain Enchytraeidae. Since their genital organs are so much like those of the Lumbriculidae, it is generally agreed that they have a common origin with that family. Both these families have the combined male ducts opening to the outside on the segment that contains the hinder pair of testes. In many re- spects the Branchiobdellidae are only modified Lumbriculidae. Their re- lationships are shown in the accompanying diagram from Stephenson (1930:705). Lumbricidae Megascolecidae-Eudrilidae Glossoscolecidae Aeolosomatidae Naididae a ee Tubificidae ? Enchytraeidae ————_Preorslidae Moniligastridae Hirudinea Common ancestor of Branchiobdellidae Megadrili Haplotaxidae Lumbriculidae DIAGRAM OF RELATIONSHIPS (AFTER STEPHENSON, 1930) Michaelsen (1919b-:152) points out the similarity between leeches and oligochaetes and that the most significant difference is the position of the testes, posterior to the ovaries in Hirudinea and anterior in the Oligochaeta. So he proposes the following natural classification of annelids: KREIS ANNELIDES I. Klasse Archiannelides II. Klasse Chaetopoda 1. Ordnung Protochaeta 2. Ordnung Polychaeta III. Klasse Clitellata 1. Ordnung Oligochaeta 2. Ordnung Hirudinea IV. Klasse Echiuroidea V. Klasse Sipunculoidea The two families, Branchiobdellidae and Acanthobdellidae, link the Oligochaeta and Hirudinea inseparably. Frank Smith (1920) reported this work in English, and at the time seemed to agree with the proposed classification. 22 ILLINOIS BIOLOGICAL MONOGRAPHS VII. CHARACTERS OF TAXONOMIC SIGNIFICANCE STEPHENSON (1930:796) calls the Branchiobdellidae a homogeneous group. However, even though they are very similar in structure, there are distinct generic and specific differences. Below are discussed the various morphological characters which the writer believes to be of diag- nostic significance. 7 8 A. Bopy SHAPE While the shape of the body is somewhat variable it seems to correlate fairly well with other characters as a basis for generic description. For example, the flattened shapes of Xironodrilus and Xironogiton, as described above (page 13), are quite distinctive. B. DorsaL APPENDAGES The presence of distinct dorsal appendages, described above, has been used by Moore (1895a) as a generic character in establishing the genus Pterodrilus and followed by Ellis (1919) in describing additional species of this genus. Yamaguchi (1934:180) doubts the generic value and per- haps even the specific value of these dorsal appendages: The dorsal appendages are known to be present in several species belonging to Pterodrilus and Ceratodrilus. According to Moore (1894) [1895a], Pt. alci- cornus and Pt. disticus are provided with dorsal transverse ridges and wing-like or cylindrical appendages located in the free margin of the ridges. Ceratodrilus thysanosomus also bears dorsal appendages extending from the dorsal transverse ridges (Hall, 1914). Digitiform dorsal appendages have been described in two Japanese species. Stephanodrilus cirratus and St. uchidai, which was at that time referred to Ceratodrilus (Yamaguchi, 1932a). The digitiform appendages of these species are mounted on dorsal transverse ridges which become lamelliform in cirratus, while in uchidai the ridges are rather inconspicuous so that the present writer overlooked them in his previous work (19322). According to Moore (1894), the dorsal transverse ridges of Pt. alcicornus are supported by dorsal segmental muscle fibers connecting the anterior with the posterior covering of hypodermis. Similar dorsal muscle fibers are also found in the dorsal transverse ridges of cirratus and uchidai. In the former species these fibers are quite conspicuous in highly developed ridges. The dorsal segmental fibers seen in these three species are found only on the dorsal side and are distinguishable from longitudinal muscles running the whole body length by their position and short length. The muscle fibers are probably identical to the ‘“Langsmuskelzelle des Nebensystems” described by Schmidt (1903) in his study on the musculature of Branchiobdella parasita. Stephanodrilus sapporensis is destitute of dorsal appendages but is marked by a low conspicuous ridge supported by a few dorsal segmental muscles. In other species of Stephanodrilus, ie, in St. inwkaii n. sp., St. megalodentatus n. sp. etc., neither dorsal transverse ridges or dorsal appendages are present. The dorsal segmental muscles could not be detected in these species. From these facts it seems to the present writer that the dorsal ridges appear along with the develop- ment of the dorsal segmental muscles. In a previous paper (1932a) it is stated that in Ceratodrilus uchidai=Stephanodrilus uchidai the dorsal digitiform appendages are present in the six trunk somites III-VIII, each somite bearing twelve of them. As the result of examination on abundant specimens of the species collected from various localities it has been clear that there are several intergrades in regard both to number of somites bearing appendages and to the appendages on each somite. Some forms are also provided with appendages in the ~) 2 BRANCHIOBDELLIDAE OF CRAY FISHES—GOODNIGHT S six trunk somites III-VIII but they are variable in number according to the somites (maximum 12 and fewer in the more anterior ones). In others the ap- pendages are more reduced in number and disappear in several anterior somites, finally disappearing altogether in all trunk somites. In these several forms the dorsal transverse ridges are always present accompanying the dorsal segmental muscle fibers. According to Ellis (1920) [1919] description and figures, Pterodrilus durbani seems to be also provided with dorsal transverse ridges, but to be destitute of distinct appendages except two “horns” found in the eighth trunk somite. Moreover, Branchiobdella kobayashti n. sp. has dorsal transverse ridges supported by dorsal segmental muscle fibers while Br. orientalis n. sp., and Br. pentadonta and others are destitute of the ridges. Judging from these facts, those provided with the dorsal transverse ridge, or dorsal segmental muscles, are not distinctly separated from those lacking them. However, it seems to the writer that Yamaguchi’s position is some- what unjustified and that at least with the American forms the dorsal appendages are of generic significance. For example, in Pterodrilus, while there are specific differences, the appendages are similar enough to allow grouping into one genus. It seems that Yamaguchi has grouped forms diverse enough to be in several genera in the genus Stephanodrilus. In regard to Stephanodrilus uchidai, he is not even sure he is dealing with only one species. He merely says: ‘As the variation occurs in series all seem to belong to a single species.” C. PERISTOMIUM The character of the peristomium appears to be of specific taxonomic value but not generic. Pierantoni (1912) believed the presence of a plurilobate peristomium to be of generic significance. Ellis (1919:256), when reviewing the genus Cambarincola, first expressed doubt of this view. He questioned it as follows: One of these characters, “the plurilobate prostomium” is particularly note- worthy in this connection as it is used by Pierantoni to differentiate Stephanodrilus in his generic key. The two species C. philadelphica and C. chirocephala have lobate lips similar to the lips of Stephanodrilus japonicus Pierantoni as figured by Pierantoni. Neither Stephanodrilus koreanus Pierantoni nor Stephanodrilus japonicus Pierantoni, however, are figured with accessory sperm tubes, and the accessory sperm tube is present in species of Cambarincola. Pierantoni also figures Branchiobdella digitita Pierantoni, a species having but a single pair of testes (Pierantoni), with a plurilobate prostomium, showing that the lobate lip character occurs in that group of species. Yamaguchi (1934:182) expresses the writer’s view when he says: The bilobate or pluri-lobed peristomium which was regarded as one of the generic characters by Pierantoni (1912) seems to be of no significance for generic value, because the two kinds of peristomia are found in one genus as will be stated below. In the genus Branchiobdella a pluri-lobed peristomium is found in Br. digitata, Br. muinuta (Pierantoni 1912) and Br. parasita (Whitman 1882), while other species have a bilobed peristomium. On the other hand, Cambarin- cola chirocephala, C. philadelphica (Ellis 1920) [1919] and C. okadai (Yamaguchi 1933) are provided with a pluri-lobed peristomium, but other species belonging to the genus are provided with a bilobed peristomium. Though the present writer (1932a) distinguished the funnel-shaped peristomium from that not funnel-shaped, the distinction is not clear in several species. 24 ILLINOIS BIOLOGICAL MONOGRAPHS D. Jaws The number and arrangement of teeth on the jaws seem to be of specific importance, although there is considerable individual variation in some species. Variations in the dental formulae of several different species are given by Ellis (1919), from which the accompanying tables have been adapted. TaBLeE I.—VARIATIONS IN THE DENTAL FORMULA OF Xitronodrilus formosus ELLIS Dental formulae Locality 4-3 4-4 5-4 5-5 6-5 7-5 Irondale, Anderson, Ind................. 3 4 17 13 4 1 Noblesville, Inds o...6..:5 css oc. acgia ace -aseiase, donne 1 1 4 oe ne 5 Charlevoix, Michis. oc. 5..:6s0:0j0.0 sales ened ae a 1 - 2 Vincennes, Ind................0 000 seen me Ss 2 1 BY Number of specimens............24.. 4 5 24 14 6 1 TABLE I],— VARIATIONS IN THE DENTAL FORMULA OF Xironodrilus pulcherrimus (Moore) Dental formulae Locality 3-3 4-3 4-4 5-4 5-5 Blowing Rock; Ni Ci. aves cauaatnecan 2 os a ee Cheat River, W. Va..............005 ue one 2 6 ee Cheat Bridge, W. Va...............- a us 3 Sie Shavers Fork, W. Va..............-- 2 Ar ee 1 1 Cheat River; Wi Vals oss.0eacccia ain sia Ae “% 1 8 os Indian Creek, W. Va..............4- ne bes 1 ae a Queens, W. Vass siecnt sacsteadevora dass < vs fe ae 7 1 ‘Trubies Run, W.. Vases sisraccea a cae. is ~~ 1 4 Baileyville, W. Va............002e00- ae = 1 ae Number of specimens............ 2 a 5 30 2 TABLE IIJ.—VARIATIONS IN THE DENTAL FORMULA OF Xironogiton oregonensis ELLIS Dental formulae Locality SS SaaS De 4-4 5-4 5-5 6-5 6-6 7-6 Bucenes Oreks a2 5 sssaneiiete. cagnst seer 1 8 3 2 a i Sequallitchew Lake, Wash............... = ae Pa 4 1 3 Number of specimens.............+4 1 8 3 6 1 3 BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 25 From a total of 37 specimens of Xironogiton instabilius (Moore) ex- amined from various localities in New York, Virginia, West Virginia, and North Carolina, Ellis found 16 with a +4 formula, 11 with a 5-4 formula, and 10 with a 5-5 formula. We could go on citing other species, the great variation in formulae of Cambarincola philadelphica (Leidy), etc., but this is sufficient to show that in nearly all species sufficiently studied there is a great diversity of dental formulae. However, in spite of this variation, individual formulae are sufficiently similar to be of specific importance. In fact Yamaguchi (1934:184) suggests that in some cases the dentition may be of generic importance when he uses it as a character to separate Stephanodrilus and Cambarin- cola as follows: Stephanodrilus Dorsal dental plate.... Provided with seven or more Cambarincola Provided with five teeth, a Ventral dental plate. . . teeth, median one larger than lateral ones. Similar in dentition to the dor- sal plate. large median and four small lateral ones. Provided with four teeth, hav- ing no median unpaired teeth (except in C. okadai bear- ing same dentition as dorsal plate). The writer considers the dentition and general shape of the jaws to be of specific but not generic importance. E. Posirion oF CAUDAL SUCKER Whether the sucker is ventral, as in Nironodrilus, Nironogiton, etc., or terminal, as in Cambarincola and others, seems to be of some generic significance when correlated with the general shape of the body. F. SHAPE OF GuT While the gut varies considerably in shape, depending on the amount of food present and the amount of contraction of the specimen, its general shape may in some cases be used as an additional specific diagnostic character. However, it is not an important taxonomic character. G. PHARYNGEAL DIVERTICULA Ellis (1919:243) says: From the sections studied the number and position of the major pharyngeal diverticula and the presence or absence of buttress-like supports of connective tissue attached to the intersegmental partitions were considered of taxonomic value. The major pharyngeal diverticula may be seen to best advantage in sagittal sections but may be located in good whole mounts of compressed worms. These pharyn- geal diverticula are not to be confused with the slight invaginations of the pharyn- geal wall nor with the fold in the pharyngeal wall near the posterior end of the pharynx (found in many preserved specimens), due to the pushing forward of the esophageal portion of the alimentary canal so that the anterior end of the esopha- gus partly telescopes the posterior end of the pharynx. 26 ILLINOIS BIOLOGICAL MONOGRAPHS But Yamaguchi (1934:183) throws doubt on the importance of pharyngeal diverticula: But it was difficult for the present writer to distinguish the “major pharyngeal diverticula” from the “slight invaginations.” It seems to be quite doubtful, there- fore, whether one should consider the number and position of the “major pharyn- geal diverticula’ as an important taxonomic character. The writer agrees with Yamaguchi that their taxonomic value is doubtful. H. OPENING OF THE ANTERIOR NEPHRIDIA The paired or unpaired condition of the pores by which the anterior nephridia open to the outside seems to be of generic importance. For example, Cambarincola has a single pore while Xironodrilus, Xironogiton, and Branchiobdella have paired pores. In the genus Stephanodrilus, Yamaguchi (1934) has described S. koreanus Pierantoni as having a single pore while all the remaining species of the genus have paired pores. But here again, in this diverse genus, several genera may well be included. I. NUMBER oF TESTES The genus Branchiobdella is separated from all other genera by the presence of a single pair of testes located in segment V. All other known genera have two pairs located in segments V and VI. This has been the basis of separating the two subfamilies, Branchiobdellinae and Cam- barincolinae. J. Accessory SpERM TUBE The accessory sperm tube, described by Ellis (1912) as a generic character of Cambarincola, consists of a blind tube arising from the spermatic vesicle and extending anteriorly. This is, according to Yama- guchi, homologous to the blind tube present in other species of other genera. It is very distinct and can clearly be seen in cleared whole mounts. It seems to be of generic importance, occurring in the genera Cambarin- cola and Xironogiton. K. PENIS Certain genera, as Cambarincola, appear to have non-eversible penes, while others, as Cirrodrilus, are eversible. The character of the penis provides characters which are constant within certain groups, and there- fore seems to be of generic significance. L. SHAPE OF THE SPERMATHECA The various shapes of the spermatheca seem to be of specific sig- nificance but have no generic importance with possibly one exception, namely, the bifid spermatheca of Bdellodrilus. However, only one species of this genus is known, and further study may reveal that this character is of specific value only. BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 27 VIII. CLASSIFICATION OF THE AMERICAN BRANCHIOBDELLIDAE IN THE FOLLOWING classification, the characterizations of the Class and Order are translations from Michaelsen (1919:153). PHYLUM ANNELIDA.—Triploblastic coelomate worms character- istically having a metanephridial excretory system, a ventral nervous system, and a dorsal blood vessel. Segmentation is typical but not universal. CLASS CLITELLATA.—Annelids with well-developed outer and inner metamerism, without parapodia, and without feelers, tactile cirri and ordinary cirri, mostly without gills; hermaphroditic. Gonads in a few definite segments. Clitellum present. Development is direct; in the main, fresh-water and land animals. ORDER OLIGOCHAETA.—Clitellum present, mostly with setae in the skin. Segments mostly single or slightly and unequally divided. Coelom well developed, large. Testes anterior to the ovaries, generally one or two pairs. SUPERFAMILY BRANCHIOBDELLOIDEA Hall, 1914 Body divided into two regions, a head and a trunk, the latter termi- nated by a sucker; without setae; mouth provided with two chitinous jaws; two pairs of nephridia; testes in pairs in fifth or in fifth and sixth segment; ovaries in the seventh segment; unpaired spermatheca in the fifth. FAMILY BRANCHIOBDELLIDAE With the characteristics of the superfamily. In the present study the writer has become impressed with the fact that the family Branchiobdellidae contains two distinct groups of genera. The sharpness of this distinction warrants the recognition of two separate subfamilies. In proposing Branchiobdellinae and Cambarincolinae as new subfamilies, the following diagnosis is presented: BRANCHIOBDELLINAE.—Pranchiobdellidae with only one pair of testes, located in the fifth segment. CAMBARINCOLINAE.—Branchiobdellidae with two pairs of testes, located in the fifth and sixth segments. SUBFAMILY BRANCHIOBDELLINAE new subfamily Branchiobdellid worms having one pair of testes and male funnels located in the fifth segment. Type and only genus: Branchiobdella Odier, 1823. 28 ILLINOIS BIOLOGICAL MONOGRAPHS GENUS BRANCHIOBDELLA Odier, 1823 Branchiobdella, Odier 1823. Mem. Soc. d’Hist. Nat. de Paris 1:75. Branchiobdella, Pierantoni 1912. Ann. Mus. Zool. Univ. Napoli, N.S. 3(24):9. Branchiobdella, Stephenson 1930:800. Branchiobdella, Yamaguchi 1934. Jour. Fac. Sci. Hokkaido Imp. Univ. 3:185. With the characteristics of the subfamily; spermatheca simple, not bifid; penis eversible; no accessory sperm tube; anterior nephridia open- ing to the outside by separate pores in segment II]; body cylindrical, not flattened; without body appendages. Type species: Branchiobdella astact Odier, 1823, from western Europe. KEY TO AMERICAN SPECIES OF THE GENUS BRANCHIOBDELLA 1. Dorsal and ventral jaws dissimilar with a 5-4 dental formula; peristomium CNHTE a ccose elena saaieeaeslen hele Branchiobdella americana Pierantoni, 1912 2. Dorsal and ventral jaws similar with a 4-4 dental formula; peristomium MiUlODER tans cas tee eeetioeeies ates Branchiobdella tetradonta Pierantoni, 1906 Branchiobdella tetradonta Pierantoni, 1906 Branchiobdella tetradonta, Pierantoni 1906b. Ann. Mus. Zool. Univ. Napoli, N.S. 2(11). Branchiobdella tetradonta, Ellis 1912. Proc. U.S.N.M. 42:485. Branchiobdella tetradonta, Pierantoni 1912. Ann. Mus. Zool. Univ. Napoli, N.S. 3 (24). Description (based on Pierantoni 1912): Peristomium divided into two lips, a dorsal and a ventral; head dis- tinctly separated from body. Body rather uniform throughout, not en- larged in median portion. Posterior sucker cup-like, not very prominent. Length about 2.0 mm. Jaws similar, bearing four equal teeth placed in a row, the two median ones sometimes a little shorter than the outer ones. Spermatheca shaped like an hour glass, with a short passage tube “condotto di uscita.” Atrium enlarged and sack-shaped. Type: From Klamath River, Calif., on Astacus klamathensis. Previous locality record: Pierantoni, 1906b, N.S. 2 (No. 11)— Klamath River, Calif., on Astacus klamathensis. Remarks: The present writer has not examined this form. Brancliobdella americana Pierantoni, 1912 Branchiobdella americana, Pierantoni 1912, Ann. Mus. Zool. Univ. Napoli, N.S. 3(24) :1-20. Branchiobdella americana, Hall 1914. Proc. U.S.N.M. 48:190-192. Description (based on Pierantoni 1912): Peristomium entire, a little enlarged to form a sucker; head very distinct from body, circumbuccal ring of papillae present; body not BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 29 “swollen” towards the middle; body semi-cylindrical; posterior sucker slightly prominent; clitellum slightly visible. Length about 5.0 mm. Jaws unequal, the dorsal provided with a large median tooth and with two pairs of smaller median teeth; the ventral with two large teeth and two smaller ones. The spermatheca in this species is in the form of an hour glass with short neck; without terminal process. The male atrium is_ slightly enlarged. Type: Material from Texas on Cambarus viridis (according to Pierantoni), C. latimanus, and C. hayi, and from Raleigh, N. C., on C. rusticus, C. immunis, and C. sp. Previous locality records: Pierantoni 1912, N.S. 3(24)— 1. Texas, on Cambarus viridis, C. latimanus, and C. hayi 2. Raleigh, N. C., on C. rusticus, C. immunis, and C. sp. Allen 1933 :119— 1. Durham, N. C. New locality records: 1. Cleveland, N. Y., on Cambarus bartoni robustus. Remarks: The material examined by the writer from Cleveland, N. Y., agreed very well with the above description. However Pierantoni failed to mention the large everted penis, which was quite evident in the writer’s specimens, SUBFAMILY CAMBARINCOLINAE new subfamily Branchiobdellid worms having two pairs of testes and male funnels located in the fifth and sixth segment. Type genus: Cambarincola Ellis, 1912. KEY TO THE GENERA OF SUBFAMILY CAMBARINCOLINAE 1 Ga) 2 Body “with: appendagess o520.cics5 v0 Gecucoduiae seat assedeecisn te ciedowsaease 2 (Cb) * Body without appendages: occ asd gece wwcwdareren Secee Beas ren ies cons ed oe 3 2. (a) Appendages in the form of blunt cylindrical projections along the median dorsal line of body... .....00.0 0500608 0000026: Pterodrilus Moore, 1895 (b) Appendages in the form of pointed bands encircling the dorsal surface OL the DOdY..56 25.2.0eec oanecrrcdeee Mesinaneaesan Cirrodrilus Pierantoni, 1905 3. Ca). Accessory sperm tube presents..c.cc.c. c.r ce an co cde neta ses omens ees 4 b) Accessory: spérm -tubé absetitins..iicasiuasccocecdshawacwien oe eenenccsadle sdwed 4. (a) Body cylindrical, not flattened, posterior end not conspicuously en- larged, anterior nephridia opening to the outside through a single pore Sve aerate aisles a atone ania Walaa ariel en aaa eie aoa cette Cambarincola Ellis, 1912 (b) Body flattened, posterior end enlarged, so that body is racket- or spatula-shaped, anterior nephridia opening to the outside through S€parate POTES).booss.s4 wo vssece tad seem ese ae dloadawels Xironogiton Ellis, 1919 5. (a) Pair of large clear glands in each of the nine postcephalic segments; spermatheca: bifidcsescsdetesa eka aeees. cedea tees Bdellodrilus Moore, 1895 (b) Without a pair of large clear glands in each of the nine post-cephalic segments; spermatheca not bifid...... 22.0... 0.0 ccc cece eee eee eee neces 6 30 ILLINOIS BIOLOGICAL MONOGRAPHS 6. (a) Major annulations of body segments secondarily divided especially noticeable in the median segments...............+-- Triannulata new genus (b) Major annulations of body segments not secondarily divided............. 7 7. (a) Body flattened; sucker ventral.............0.00eee: Xironodrilus Ellis, 1919 (b) Body not flattened; sucker terminal........ Stephanodrilus Pierantoni, 1906 GENUS CAMBARINCOLA Ellis, 1912 Astacobdella, Leidy 1851. Proc. Acad. Nat. Sci. Phila. 206. Branchiobdella (in part), Moore 1894. Proc. Acad. Nat. Sci. Phila. 427-428. Bdellodrilus (in part), Pierantoni 1912. Ann. Mus. Zool. Univ. Napoli, N.S. 3(24). Cambarincola, Ellis 1912, Proc. U.S.N.M. 42:481-485. Cambarincola, Hall 1914. Proc. U.S.N.M. 48:190-192. Cambarincola, Ellis 1919. Proc. U.S.N.M. 55:255-264. Cambarincola, Stephenson 1930:801-802. Cambarincola, Yamaguchi 1932c. Proc. Imp. Acad. 8(9) :454-456. Cambarincola, Yamaguchi 1933. Proc. Imp. Acad. 9(4) :191-193. Cambarincola, Yamaguchi 1934. Jour. Fac. Sci. Hokkaido 3(3) :189-191. With the characteristics of the subfamily; spermatheca simple, not bifid; accessory sperm tube present; bursa but not penis eversible; an- terior nephridia opening to the outside through a common pore situated on a median dorsal papilla; body cylindrical not flattened; without body appendages. Type species: Cambarincola macrodonta Ellis, 1912. KEY TO THE SUBGENERA OF CAMBARINCOLA 1. Upper lip composed of four subequal lobes.............. Coronata new subgenus 2. Upper lip entire excepting a small median emargination................000 SN Die se RM Gara bo eke tee aetmamieeeeee ees Cambarincola new subgenus SUBGENUS CAMBARINCOLA new subgenus With the characteristics of the genus Cambarincola; upper and lower lip entire excepting a small median emargination in all but C. inversa which has two small lobes in the base of the emargination. Type species: Cambarincola macrodonta Ellis, 1912. KEY TO THE AMERICAN SPECIES OF THE SUBGENUS CAMBARINCOLA 1. (a) Major annulation of segment VIII visibly and distinctly elevated over minor annulatiOns.. << <:sjsacsies celais Guave aszave Cambarincola elevata new species (b) Major annulations of segment VIII not distinctly elevated over minor AMT AO io) syops ioe cecyeusysydee eel aleue:aue te alae cans oa stew lass caine! anniehoncnstan ane faysun (favsun aleyalcaarere a 2 2. (a) Upper jaw with three prominent teeth; if, as in a few specimens, five teeth are present the two lateral ones are very small.................. seisais wg Re Aeon EA cee aS Oe te eas Cambarincola inversa Ellis, 1919 (b) Upper jaw not as above but with five noticeable teeth..................4- 3 3. (a) Middle tooth of upper jaw long and prominent when compared with the small lateral teeth... 2..:.60.000..205 Cambarincola macrodonta Ellis, 1912 (b) Middle tooth of upper jaw longer than the other four teeth but small enough that all five teeth may be considered subequal................. MN cs, acpe are eas nee ara ai MOE eee Cambarincola vitrea Ellis, 1919 BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 3l Cambarincola (Cambarincola) macrodonta Ellis, 1912 Cambarincola macrodonta, Ellis 1912. Proc. U.S.N.M. 42:481-486. Cambarincola macrodonta, Hall 1914. Proc. U.S.N.M. 48:190. Cambarincola macrodonta, Ellis 1919. Proc. U.S.N.M. 55:257, Description from Ellis 1912:481-486: “Body rather slender when extended, slightly arched ventrally, cir- cular in cross section in all regions, greatest diameter in the fifth or sixth segment, shortest diameter in the first segment, sloping gradually from the fifth segment to the first and rather abruptly from the sixth segment to the acetabulum; greatest diameter of the head always less than the greatest diameter of the body; greatest diameter of the body 5 to 8 in the body length; head distinct, elongate in extended specimens; length of the head greater than the greatest diameter of the body in extended specimens (greatest diameter of the body 1.1 to 1.3 in the length of the head), equal to or less than the greatest diameter of the body in con- tracted individuals (length of the head 1 to 1.3 in the greatest diameter of the body); greatest diameter of the head 1.2 to 1.4 in the greatest diameter of the body. “Head composed of four annulations; the first or anterior cephalic annulation very prominent, of less diameter than the second annulation, tapering forward, from 2.3 to 3.3 in the total length of the head, depend- ing upon the degree of contraction, composed largely of two fleshy lips— a dorsal and a ventral—of which the dorsal is very slightly the longer ; the other three annulations very indistinctly marked, so that the remainder of the head appears to be but a single piece; first seven or eight body segments showing a rather distinct biannulation, the anterior portion of each segment being of the greater diameter; acetabulum terminal, of moderate size, from 1 to 1.25 in the greatest diameter of the head; genital papillae on segments 5 and 6, quite conspicuous in large specimens. “Mouth terminal, or very slightly ventral, its opening rather diamond shaped, with the greatest dimension at right angles to the dorso-ventral line, guarded by two large lips, each of which bears several tiny papillae on its inner surface and a few minute hairs on its outer edge near the median line; each lip entire with the exception of a single slight emargi- nation in the median line, which may be entirely wanting; dental plates very dark-brown to black, situated at or just in front of the junction of the first and second cephalic annulations; dorsal plate roughly triangular in outline when seen from the front, middle portion of the base exca- vated so that the two corners extend beyond the rest of the plate as two horns, anterior face with two rather prominent teeth on each side near the edge of the plate, the tooth nearer the apex on each side being pointed and larger than the basal tooth, apex produced into a single large cylindrical tooth with a conical point; ventral plate with an excavated base like that of the dorsal plate, the anterior face bearing a single small 32 ILLINOIS BIOLOGICAL MONOGRAPHS knob-shaped tooth on each side near the base, apex produced into two large cylindrical teeth, each with a conical point. “Pharynx narrowing just behind the dental plates, with a distinct dorsal diverticulum near the junction of the second and third cephalic annulations and a ventral diverticulum slightly caudad, the mouths of the two diverticula producing an irregular enlargement of the pharynx in the third annulation; esophagus narrow, occupying the first body segment, near the middle of which it drops to the floor of the body cavity; crop or post-esophageal portion of the alimentary canal extending through seg- ments 2 and 3, rising gradually to the center of the body, increasing steadily in diameter, caudad, and showing little or no constriction at the junction of segments 2 and 3 unless distended with food; stomach large, almost filling segment 4, marked off by definite constrictions ; intestine proceeding as a straight tube of slightly less diameter than that of the stomach through the center of segments 5 and 6; in segment 7 becoming somewhat narrowed, swinging dorsally and to the left side of the body in the anterior portion of the segment, and returning much narrower to the right of the median line in the posterior portion of the segment, leaving segment 7 near the dorsal wall of the body cavity; continuing in the anterior portion of segment 8 much narrower, crossing again to the left side and descending to the center of the segment, enlarging in the posterior portion of the segment, but leaving segment 8 near the center as a small tube; the rectum beginning in segment 9, passing diagonally through this segment to its dorsal wall, opening dorsally in the median line in the anterior portion of segment 10. “Living animals colorless and quite transparent excepting the ali- mentary canal (which was a pale green in the specimens observed), and the gonads; body quite contractile.” Type: U.S.N.M. No. 53794 from Boulder, Colo., on Cambarus diogenes Girard. Length 4.65 mm. Previous locality records: Ellis 1912:481— 1. Boulder, Colo., on Cambarus diogenes. Ellis 1919:251— . Fort Clark, Tex., on C. clarkii. New Orleans, La., on C. diogenes ludovicianus. Sims Bayou, Houston, Tex., on C. blandingti acutus. Lake Lapoudre, Morgan City, La., on C. clarkii. . Frierson, La., on C. blandingii acutus. Las Vegas, N. M., on C. gallinas. . Muldon, Miss., on C. hagenianus. . Black Wolf Creek, near Beecher’s Island, Colo., on C. diogenes. . Arikaree River near Beecher’s Island, Colo., on C. diogenes. 10. Boulder, Colo., on C. diogenes. New locality records: 1, Leaf River, Ill, on C. virilis. 2. Macoupin Co., Ill., on C. virilis. _ CONAN WN BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT wW Ww Champaign Co., Ill, on C. virilis, C. immunis, and C. propinquus. Oakwood, IIl., on C. propinquus. . Botetourt Co., Va., on C. bartonii. Mena, Ark., on C. menae. . Dent Co., Mo., on C. medius. . Omaha, Neb., on C. imamiumnts. ONDA p Ww Remarks: The above quotation describes very accurately this species which has little variation despite its large geographical range. Cambarincola (Cambarincola) vitrea Ellis, 1919 Cambarincola vitrea, Ellis 1918. Trans. Amer. Micr. Soc. 37:49-51. Cambarincola vitrea, Ellis 1919. Proc. U.S.N.M. 55:257-258. Description from Ellis 1919:257-258: “Body and head subterate, little if at all depressed; diameter of the head approximately equal to that of segment IJ, usually slightly greater than that of segment I; body segments II to VIII subequal, segments V, VI, and VII when distended with sex cells slightly wider than segments III and IV; segments posterior to VIII narrowing rather rapidly to the caudal sucker, the diameter of which is less than of the head; all body segments easily visible in side view; major annulations distinct, but very slightly elevated above the minor annulations; head divided into three subequal parts, the anterior being the most distinct of the three; lips two, subequal, each with a small, median emargination; major pharyngeal diverticula two, the dorsal slightly anterior to the ventral; a few short bristles present on each lip; dental formula 5-4; ... . alimentary canal straight, following the mesial line of the body, maximum enlargement in segment IV ; anterior nephridia opening to the outside through a common pulsatile pore on the dorsal surface of the major annulation of segment III; spermatheca simple and tubular; testes present in segment V and VI, vasa deferentia from segments V and VI meeting the atrium in segment VI; accessory sperm tube present; largest specimen examined, 4.7 mm. “This species superficially resembles Xironodrilus formosus Ellis, both in body form and type of jaws. In addition to the several generic char- acters by which these two species may be separated, it may be noted that the jaws, although having the same number of teeth and the same general form, are quite different.” Type: U.S.N.M. 17668 from Douglas Lake, Mich., on Cambarus viriis Hagen. Length: 310 mm. Previous locality records: Ellis 1918:49-51— 1. Douglas Lake, Mich., on Cambarus virilts. 2. James Island, Potagannissing Bay, Mich., on C. virilis. 3. Three miles up Potagannissing River, Drummond Island, Mich., on C. virilis. 4. Sault Sainte Marie, St. Marys River, Mich., on C. propinquus. 5. Echo Lake, Grand Island, Lake Superior, Mich., on C. propinquus. 34 ILLINOIS BIOLOGICAL MONOGRAPHS Ellis 1919:257-258— 1. Rhinelander, Wis., on C. wirilts. 2. St. Vraine, Colo., on C. timunts. 3. Rolla, Mo., on C. wirilis. 4. Maple River, Douglas Lake, Mich., on C. propinquats. 5. Lake Huron, Cheboygan, Mich., on C. propinquus and C. virilts. 6. Grapevine Point, Deuglas Lake, Mich., on C. propinquus. 7. Wellington, Ill., on C. virtlts. 8. Urbana, Ill, on C. virilts. 9. Arikaree River, near Beecher’s Island, Colo., on C. virtlis. 10. St. Marys River, Fort Wayne, Ind. (host not given). 11. Mouth of Carp River, St. Martins Bay, near Straits of Mackinac, on C. virilis. New locality records: 1. Leaf River, Ill, on C. virilts. 2. Lake Geneva, Wis., on C. virilts. 3. Macoupin County, Ill, on C. blandingii acutus, C. virilis, C. tmmunis, and C. propinquats. 4. Oakwood, Hl., on C. propinguas. 5. Punta Gorda, Fla., on C. sp. 6. Stillwater, Okla., on C. sp. 7. Tuscaloosa, Ala., on C. sp. 8. Cleveland, N. Y., on C. bartonit. 9. Alpha, Ky., on C. placidus. 10. Odessa, Mich., on C. propinquus. 11. Indianapolis, Ind., on C. rusticus. 12. Lisbon, N. D., on C. virilis. 13. Dallas, Tex., on C. stmulans. 14. Hayward, Wis., on C. wvirtlis. 15. Marathon, Wis., on C. virilts. 16. Pittsville, Wis., on C. virilis. 17. Glen Flora, Wis., on C. wirilis. 18. Swastika, Ontario, on C. virilis. 19. Holcombe, Wis., on C. virilis. 20. Noxubee County, Miss., on C. misstsstppiensts. 21. Galloway, Mo., on C. longidigttus. 22. Emette Co., Mich., on C. propinquus. 23. St. Marys River, Ontario. Remarks: This form could be confused with Cambarincola macro- donta, but it is easily distinguished by the difference in tooth structure as outlined above. Cambarincola (Cambarincola) elevata new species (PIL. I, Fig. 3; Pl. II, Fig. 5) Description: Length of mature worms varying between 2.0 and 3.0 mm. The head diameter approximately equal to segment II, slightly greater than seg- ment I, Segments increasing in diameter to segment VI or VII which is about 0.4 mm. in a worm 2.5 mm. long, then decreasing rapidly to the caudal sucker, whose diameter is slightly less than the head; sucker terminal; body little if at all depressed. Major annulations distinct; all BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 35 except segment VIII but very slightly elevated over minor annulations ; major annulation of segment VIII distinctly and visibly elevated over the minor annulation so as to almost obscure it. Head divided into three subequal parts; peristomium divided into two lips each with a slight median emargination. Jaws small, about 15-20 microns in a 2.5 mm. worm with a tooth formula of 5-4. The alimentary canal is straight following the mesial line of the body with the maximum enlargement in segment IV ; anus present in the dorsal half of segment X. Two pairs of testes present, one pair in segment V and one pair in VI; vasa deferentia joining the atrium in VI; distinct accessory sperm tube present in VI. Bursa but not penis eversible. Ovaries in segment VII; spermatheca in V consists of three parts, a short muscular portion near the spermathecal pore, a short middle tubular portion, and large dorsal globose part, resembling the spermatheca of Xironodrilus for- mosus; anterior nephridia opening to the outside through a common pore in the dorsal half of segment III. Holotype: From Leaf River, Ill. on Cambarus virilis. Paratypes: From Macoupin Creek near Carlinville, Ill., on Cambarus virilis; Buck Creek near Penfield, JIl., on C. virilis; Leaf River near Byron, Ill., on C. virilis; Seven Mile Creek, Rock River Drainage, III, on C. virilis and C. propinquus; and Lake Geneva, Wis., on C. virilis. Additional material: Farmington, Mo., on C. pitinctimanus; lowa River, Iowa, above Junction of Upper Iowa River; Oxford, Ontario. Remarks: This species is closely related to C. vitrea, but differs in the elevation of the major annulation of segment VIII and in the shape of the spermatheca which is simple and tubular in C. vitrea. The holo- type will be deposited in the United States National Museum, and para- types in the collection of Dr. H. J. Van Cleave, of the University of Illinois, and in the collection of the writer. Cambarincola (Cambarincola) inversa Ellis, 1919 Cambarincola inversa, Ellis 1919. Proc. U.S.N.M. 55:259-260. Description from Ellis 1919:259-260: “Body rather elongate and more or less terete; width of the head approximately equal to that of segment I; body segments increasing in width regularly and gradually from segment I to segment VI, which is the widest segment of the body; segments VIT and VIII slightly narrower than segment VI; body posterior to segment VIII narrowing rapidly to the caudal sucker; all eleven body segments visible in side view and nine or more visible in dorsal view; caudal sucker termino-ventral, its diameter less than that of the head; each segment slightly constricted anteriorly and posteriorly, so that the segmental junctions are distinct ; head subcylindrical, its anterior third defined by a groove or constric- 36 ILLINOIS BIOLOGICAL MONOGRAPHS tion; length of the head in a moderately expanded specimen slightly less than the length of the first two body segments; lips, two, the upper slightly longer than the lower; the lower lip with a distinct median emargination; upper lip like the lower, but with two small lobes in the base of the emargination; oral bristles present; dental formula 3-4, varying 3-3 to 5-4; upper jaw with three large teeth, of which the middle one is the longest, all three directed forward—that is, away from the base of the jaw; dental ridge of the upper jaw usually with a small tubercle in the position of the teeth of the “e” order—that is, if the jaw were five-toothed (teeth were found on these tubercles in two specimens, the tooth point in each case being very small) ; lower jaw with two large teeth and two small lateral teeth; upper jaw 20 micra wide, lower jaw 17. micra wide in an expanded worm measuring 3.6 mm.; major pharyngeal diverticula two, one dorsal and one ventral; anterior nephridia alternating in segments IT and III, opening to the outside in segment IIT through a common pore in the dorsal surface of the major annulation of segment III; spermatheca simple, long, and tubular, not bifid; testes present in segments V and VI, vasa deferentia from segments V and VI meeting in the strium in segment VI; alimentary canal straight, increas- ing in diameter in segment I, much expanded in segments I], III, and IV, in which segments it forms an almost continuous pouch; intestine nar- rowing in the posterior half of segment IV; alimentary canal following the mesial line of the body through segments V to EX, swinging dorsad through segment IX to anal opening on the dorsal surface of segment X.” Type: U.S.N.M. No. 17680 from Eugene, Ore., on Astacus klamathensis. Previous locality records: Ellis 1919:259— 1. Eugene, Ore., on Astacus klamathensis. New locality records: . Twenty-two miles from Vintago, Wash., on A. sp. . Klamath, Ore., from A. trowbridgi. . Deer Creek, Ore., on A. klamathensis. Yakima, Wash., on A. klamathensis. . Bovill, Idaho, on A. gambeli. . Minam, Ore., on A. klamathensts. Odessa, Wash., on A. klamathensis. . St. Helens, Ore., on A. trowbridgii. . Lew Co., Wash., on A. trowbridgii. 10. Cestsajo Creek, Ore., on A. trowbridgii. 11. Redmond, Wash., on A. trowbridgii. 12. Vernonia, Ore., on A. trowbridgit. 13. Silver Creek, Harney County, Ore., on A. gambelit. 14. Young River, Ore., on A. klamathensts. COANAURWNE Remarks: Although a great many specimens were studied, little variation was encountered. BRANCHIOBDELLIDAE OF CRAYFISHES—GOODNIGHT 37 SUBGENUS CORONATA new subgenus With the characteristics of the genus Cambarincola; upper lip com- posed of four subequal lobes, which may be extended as digitiform tentacles; lower lip composed of two subequal lobes which may be ex- tended also; middle tooth of upper jaw long and prominent, almost ob- scuring lateral ones. Type species: Cambarincola philadelphica (Leidy, 1851) KEY TO THE AMERICAN SPECIES OF THE SUBGENUS CORONATA 1, Major annulations of body segments distinctly and visibly elevated over Minor anna tons: