c 



1 





Fio. XI. 



1. Diagram of the anatomy of an elongated Triclad, Ehynchodemus (after Moseley), in 

 order to show the repetition of gonads and the simple character and the almost symmetrical 

 arrangement of the intestinal diverticula with which the genital organs alternate (which are 

 represented too symmetrical), a, group of eyes ; b, germ-producing follicle of the ovary ; c, 

 oviduct which receives ductules from the yolk-forming follicles (d) when these are ripe ; e, 

 testes ; /, sperm duct ; g, seminal vesicle into which the two sperm ducts open ; h, penis lying 

 in the antrum masculinum (i) ; j, common genital pore ; /.-, antrum femininum, into which the 

 two oviducts (germ-vitellarian ducts) open ; ?, pharyngeal sac ; m, mouth ; n, pharynx ; p, 

 anterior of the three limbs of the intestine ; gr, right and left posteriorly directed limbs of the 

 intestine ; oo, simple, unbranched intestinal caeca, characteristic of the Terricola. 



2. Diagram of the alimentary system of Phagocata gracilis, Leidy (after Woodworth). 

 a, eye ; b, principal (normal) pharynx ; cc, several accessory pharynges lying in the large 

 pharyngeal sac (I), and each receiving a branch from the posterior limb (qr) of the intestine ; 

 m, n, o, p, q, r, as in Fig. 1. 



