258 



ZOOLOGY 



SKCT. 



always 

 sucker 



present an anterior set of suckers (or a single anterior 

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



-mo 



ph 



ff-P 



A,, 



I/it 



FIG. 200. Monogenetic TrematOdes. 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 ; Tt 1 . caudal disc of the first embryo; 7t'-. caudal disc of the 

 second embryo; mo. mouth; oosp. oosperm ; ov. ovary; p. penis; ph. pharynx; if. tcstes. 

 B, Polystomum. en. intestine ; g. p. genital pore; mo. mouth : />/<. pharynx; or. ovary ; te. 

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

 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 



