4O2 



FRESH-WATER BIOLOGY 



125 (124) Uterus more or less elongated or in coils but not in form of a cen- 

 tral rosette 126 



126 (129) Genital pore near oral sucker on left margin of body. 



Subfamily PROSTHOGONIMINAE Liihe 1909. . . 127 



Small to medium sized distomes with body somewhat flattened and elongate. Skin spinous. 

 Pharynx present, esophagus variable, crura half or three-quarters length of body. Excretory 

 bladder Y-shaped, sometimes with caudal vesicle. Genital pore marginal, dorsal or anterior 

 to oral sucker. Cirrus sac long, slender, cylindrical, extending to or beyond intestinal bifur- 

 cation. Testes behind acetabulum and ovary. Ovary close to acetabulum, vitellaria extra- 

 cecal in central portion of body. Receptaculum seminis and Laurer's canal present. Uterus 

 in coils in posterior region, chiefly behind testes. 



127 (128) Testes symmetrical; ovary lobed; uterine coils pass between testes. 



Prosthogonimus Liihe 1899. 



From the bursa Fabricii of various water birds in Europe. Reported from North America 

 in a hen's egg and also from two birds. 



128 (127) Testes oblique or tandem; ovary entire; uterine coils do not pass 



between testes Cephalogonimus Poirier 1886. 



Genital pore dorsal or anterior to oral sucker. 

 Uterus passes from ovarian complex directly 

 posteriad between crura and testes, on right 

 side of body, forms mass of coils behind testes 

 and passes anteriad on left to genital pore. 

 Vitellaria not always entirely extracecal. 

 Testes round or irregular. Eggs numerous, 

 moderate in size, development unknown. 



Two species in intestine of frogs, Toronto 

 and Montreal; and of soft-shelled turtles 

 (Aspidonedes and A my da), Minnesota. 



FIG. 697. Cephalogonimus americanus. Living 

 animal, from ventral surface. Magnified. (After 

 Stafford.) 



FIG. 698. Cephalogonimus vescaudus. Entire 

 worm from dorsal surface, somewhat flattened. 

 Magnified. (After Nickerson.) 



FIG. 697. 



FIG. 698. 



129 (126) Genital pore anterior to acetabulum, from nearly median to 

 marginal in position. 



Family PLAGIORCHIIDAE Liihe char, emend. . . 130 

 (Syn. Lepodermatidae Odhner 1910.) 



More or less elongate distomes with moderately flattened to cylindrical body; rarely (Oche- 

 tosoma) strongly flattened. Skin usually spinous over entire body. Prepharynx, pharynx, 

 and esophagus present; crura very variable in length. Excretory bladder typically Y-shaped 

 with median stem dividing into two short branches behind complex of Mehlis' gland. Genital 

 pore usually just in front of acetabulum, slightly left of median line. Cirrus sac crescentic, 

 powerful, with prominent longitudinal fibers, containing cirrus, vesicle, and prostate; rarely 

 (Astiotrema) reduced. Ovary on posterior margin of acetabulum, dextral, rarely sinistral. 

 Testes usually oblique, rarely symmetrical or median, close behind ovary. Laurer's canal 

 present, except in Pneumonoeces ; receptaculum seminis variable. Vitellaria lateral, variable 

 in extent. Uterus extends posteriad to end of body and then anteriad to pore, simple or com- 

 plicated by coils filling posterior region. Eggs very numerous, small, thin-shelled, measure 

 20 to 50 ju. 



