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 



eni 



-v.d. 



■vik 



Fig. 200. — Monogenetic TrematOd.es. A, Gyrodactylus. til. 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 ; fcl. caudal disc of the first embryo ; h-. caudal disc of the 

 second embryo ; mo. mouth ; oogp. oosperm ; ov. ovary ; p. penis ; ph. pharynx ; te. testes. 

 B, Poh/stomum. 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 



