SCHISTOSOMUM H^MATOBIUM 



177 



broadens to a width of i mm., decreasing, however, in thickness ; 

 the lateral edges curl in ventrally, so that the posterior part of the 

 body appears almost cylindrical, 0*4 0*5 mm. in diameter; the 

 posterior extremity is somewhat more attenuated. The dorsal 

 surface of the posterior part of the body is covered with spinous 

 papillae. [These are used by 



the males to hold on to the ^^ 



wall of the veins during their 

 wanderings.] There are deli- 

 cate spines on the suckers and 

 larger ones invest the entire 

 ventral surface of the gynae- 

 cophoric canal, as well as a 

 longitudinal zone at the edge of 

 that side of the dorsal surface 

 that is covered by the other 

 edge rolling over it. The oeso- 

 phagus is beset with numerous 

 glandular cells (fig. in), and pre- 

 sents two dilatations ; the intes- 

 tinal bifurcation is close in front 

 of the ventral sucker, the two 

 branches uniting sooner or later 

 behind the testes into a median 

 trunk, in the course of which it 

 may again divide at short in- 

 tervals. The excretory pore is 

 at the posterior end, but placed 

 somewhat dorsally ; the genital 

 pore is at the beginning of the 

 gynaecophoric canal, thus behind 

 the ventral sucker ; at this spot 



FlG l09 ._ S chisto S omum 



a duct discharges, which, to- Bilh. 12/1. Male conducting the female 

 ,',,.,. , , . . into the canalis gynsecophorus. (Alter 



wards the interior, broadens into 



the seminal vesicle, and then 



continues into the excretory duct of the four or five testes (fig. in). 

 The females are filiform, about 20 mm. in length, pointed at 

 each end, and measuring 0*25 mm. in diameter in the middle. 

 Their colour varies according to the condition of the contents of 

 the intestine. [Posteriorly they are dark brown or blackish.] 

 The cuticle is smooth except in the sucker, where there are 

 very delicate spines, and at the tail end, where there are other 



T2 



