No. 2322. TREMATODE FAMILY HETEROPHYIDAE— RANSOM. 551 



diameter (Elbbrachsen) ; 360 [x in diameter, surrounded by a fibrous 

 granular envelope 90 [x thick (Barbe). Cercaria from cyst, oval in 

 shape, with a very prominent excretoi*y vesicle. Cuticle armed with 

 fine spines. Size of cercaria 0.486 mm. long, 0.36 mm. wide; oral 

 sucker 57.6 [i. in diameter; pharynx, 32.4 [jl. 



Hosts. — Immature stage (encysted cercaria) in the muscles of 

 fishes from the Rivers Elbe and Alster: Plotzen (apparently type 

 host), Brachsen, Barben, Plinten, Ukelei, etc. Young adult in 

 intestine of experimentally infected mouse. Usual host of adult 

 unknown. 



Location. — Immature stage in muscles of fish. Adult presumably 

 in intestine of fish-eating mammal or bird. 



Localities collected. — Germany (Rivers Elbe and Alster). 



So far as may be determined from Katsurada's (1914) description 

 and figures Paracoenogonirrius ovatus corresponds to Gryptocotyle., 

 the only discrepancy being in the size of the ^g'g., no previously 

 known species of this genus or of the family Heterophyidae having 

 eggs so large. The ^gg of Katsurada's species is more than twice 

 as large as that of any other species of Heterophyidae. Further 

 investigations are necessary before the form described by Katsurada 

 can be properly placed. 



Genus APOPHALLUS Luhe, 1909. 



Generic diagnosis. — Heterophyidae : Prepharynx present but much 

 shorter than the long esophagus. Bifurcation of intestine nearer to 

 ventral sucker than to oral sucker. Intestinal ceca extend into the 

 posterior end of the body well behind the testes. Ventral sucker 

 median, about midway of the body, opening to the exterior through 

 the genital pore. The genital sinus, which opens to the exterior 

 through the genital pore, and in which the vas deferens and vagina 

 terminate, is situated immediately in front of the ventral sucker. 

 Well-developed seminal vesicle behind the ventral sucker. Testes 

 globular or oval, in posterior third of body, the right testis usually 

 obliquely behind the left, but the two may be side by side at the same 

 level. Seminal receptacle in front of and to the right of the left 

 (anterior) testis. Ovary globular, on the right side of the median 

 line, in front of the seminal receptacle. Vitellaria extend forward to 

 about the level of the ventral sucker, may be limited to the lateral 

 fields in this region, but may extend inward to the median line in 

 front of the ventral sucker; posteriorly the lobules of the vitellaria 

 are numerous behind the testes and between them, and often are pres- 

 ent on the dorsal and ventral sides of the testes. Transverse vitelline 

 ducts located in the reighborhood of the boundary between the 



