398 



FRESH-WATER BIOLOGY 



branches reach to posterior margin of pharj'nx. Testes elongate, parallel, 

 dorsal, in posterior third of body; seminal vesicle convoluted, large; no 

 cirrus or sac. Ovary ventral, proximate to testes, slightly lobed; Laurer's 

 canal (?); vitellaria lateral, in central region. Uterus with descending 

 ramus on right, shghtly coiled, extending to posterior end, ascending 

 ramus returning on left, crossing anterior to ovary and passing on right 

 to genital atrium. Eggs small, dark, about 20 by 10 ^i. 



Type genus. 



Cryptogonimus H. L. Osborn 19 10. 



The genus has been placed in the Acanthochasmidae; see note under 

 82 (75). Even if that action be justified it occupies a position suffici- 

 ently isolated to demand rank in a separate subfamily as indicated 

 here. 



Only species known in North America. 



Cryptogonimus chyli Osborn 1903. 



In stomach and intestine of Micro ptencs dolomieu and AmblopHtes 

 rupestris; Lake Chautauqua, New York; St. Mary's River, Michigan; 

 Canada. Young distomes encysted in small black bass, rock bass, and 

 minnows (Cooper). 



Fig. 689. Cryptogonimus chyli. Ventral view with spines omitted and coils 

 of uterus simplified. X 9. (After Osborn.) 



107 (66) Coils of uterus extend well beyond testes into posterior portion 



of body 108 



108 (109) Mouth surrounded by a crown of six muscular papillae which 



are outgrowths of oral sucker Bimodera. 



See note under 66 in this key and description with figure under 103. 



109(108) Mouth without crown of papillae no 



no (115) Vitellaria represented by small solid more or less lobed organ on 

 each side of body just anterior to ovary. 



Family Gorgoderidae Looss 1901. 



Muscular distomes with slender mobile anterior region and flattened posterior region. 

 Suckers muscular; acetabulum especially projects noticeably beyond surface of body. Skin 

 without spines but often with fine papillae. Esophagus long without, or short with pharynx. 

 Crura simple, extend to posterior end. Excretory bladder simple tubular, extending from 

 dorsal pore near posterior end to region of ovarian complex. Genital pore median, between 

 acetabulum and fork of intestine; without male copulatory organs. Ovary lateral, post-' 

 acetabular; Laurer's canal or receptaculum seminis present. Testes lateral, obhque or sym- 

 metrical. Uterus in numerous open loops chiefly postovarian. Eggs relatively large with 

 thin, faintly colored shell. 



Only one subfamily reported in North America. 



GORGODERINAE LoOSS 1 899 



III 



Small to submedium in size, sometimes slender, sometimes broad in posterior region. 

 Esophagus relatively long, without muscular pharynx. Testes more or less oblique and within 

 intestinal crura. Laurer's canal present but no receptaculum seminis. Vitellaria not far 

 apart. 



In urinary bladder and ducts of fishes and amphibians. 



i 



