1910.] 



ENTOZOA OF THE HIPPOPOTAMUS. 



247 



The vesicula seminalis is a wide tube filling with its coils almost 

 the whole space between the atrium and the anterior testes. 



The pars musculosa is, on the other hand, almost absent, and 

 is represented only by a narrow duct discharging by a tiny pore 

 into the pars prostatica, a sausage-like dilated cavity. 



The ductus ejaculatorius is funnel-like, its thick muscular walls 

 are really a portion of the atrial musculature. It is 0"14 mm. in 

 length and unites with the metraterm to form the ductus her- 

 maphroditicus, which discharges upon the summit of an enormous 

 muscular pad. 



Text-fig. 33. 



ParampJiisiomum sellsi. Median longitudinal section. 



The yolk- glands extend from behind the pharynx to the sides 

 of the ventral sucker ; they are arranged in single file and the 

 follicles are clumped into masses of enormous size, measuring each 

 about 0"2 mm. in diameter. 



The ovary is large and oval, placed with its greatest diameter 

 (05 mm.) dorso ventrally between the posterior testis and the 

 fundus of the excretory vesicle. 



The shell-glands lie immediately behind the ovary and occupy 

 almost wholly the space intervening between it and the excretory 

 vesicle. 



The uterus passes dorsally over the testes following a fairly 

 straight course, and discharges into the metraterm 075 mm. from 

 its union with the ductus ejaculatorius. 



Laurer's canal runs from the shell-glands in an anterior direc- 

 tion, passing the ovary dorsally to open in the middle line at the 



