vii. — -- 



Fig. 165. 



gen.at. 



— vas def. 



Fig. 166. 



Figs. 165 and 166. Diagram of the arrangement of genital organs and ducts 

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

 Heterocotylea. 4. Cestoda, Dibothriata. b.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; vtt. vitellarium; 

 d* 6f $ op. common opening of genital atrium to exterior. 



