Fig. 159- 



Fig. i6o. 



Figs. 159 and 160. Diagram of the arrangement of genital organs and ducts 

 in the Platyhelminthes. i. Rhabdocoelida. 2. Tricladida. 3. Trematoda, 

 Heterocotylea. 4. Cestoda, Dibothriata. h.c. bursa copulatrix (stalked 

 organ); d.c. ductus communis; gen.at. genital atrium; Laur.c. Laurer's 

 canal; ov. ovary; p.s.o. pear-shaped (muscular) organ; pe. penis; rec.sem. 

 receptaculum seminis; sh.gl. shell glands; test, testis; ut. uterus; ut.op. 

 uterine opening to exterior; vag. vagina; vag.op. opening of vagina to ex- 

 terior; vas def. vas deferens; ves.sem. vesicula seminalis; vit. vitellarium; 

 ^ & '^ op. common opening of genital atrium to exterior. 



