258 



ZOOLOGY 



SECT. 



always present an anterior set of suckers (or a single anterior 

 sucker surrounding the mouth) and a posterior set, or a single 



B 



jbh 



en- 



ff-P 



vit. 



i/it- 



FIG. 200. Monogenetic Trematodes. A, Gyrodactiilus. cil. disc bearing hooks and pro- 

 cesses at the posterior end ; ent. intestine ; gl. unicellular glands whose ducts open on the 

 surface about the anterior end ; A 1 , caudal disc of the first embryo ; k~. caudal disc of the 

 second embryo ; uio. mouth ; oosp. oosperm ; ov. ovary ; p. penis ; ph. pharynx ; te. testes. 

 B, Polystomuin. en. intestine ; g. p. genital pore; mo. mouth ; ph. pharynx; ov. ovary ; te. 

 testes; u. uterus; v., v. d. vas deferens ; vit. vitelline glands ; vit. d. vitelline ducts; x. 

 marks the position of the genito-intestinal canal connecting the oviduct with the intestine. 

 (From M. Braun.) 



large posterior sucker. The arrangement already described as 

 characterising the Liver-Fluke is that which is typical in the 



