356 



MANUAL OF ELEMENTARY ZOOLOGY 



- tp. s. 



mtn. 



u.g.p. 



Fig. 255. — The reproductive organs of 

 a male dogfish. 



cl., Cloaca ;.//., "falciform" ligament; i.o.d., 

 rudiment of the internal opening of the 

 oviducts; Lt., left testis; msn.^ mesone- 

 phros ; ///so., mesorchium ; mta., metane- 

 1 ili mi, ;,^'j. ( cesophagus;r./., right testis; ««., 

 rectum; sp.s., sperm sac; «^^., urino- 

 genital papilla; w.f.j., urinogemtal sinus; 

 «n, ureter; w^., ducts of metanephros;z».^, 

 vasa efferentia ; ves.sent., vesicula seimn- 

 alis ; IV.d. , Wolffian duct or vas deferens. 



Wolffian duct, — corre- 

 sponding to the kidney 

 duct of the frog, runs 

 the whole length of the 

 kidney, lying upon its 

 ventral face and receiv- 

 ing the tubules of the 

 mesonephros. In the 

 female it is straight and 

 its hinder end is widened 

 to form a icrinary sinus, 

 which joins its fellow to 

 open into the cloaca 

 upon a median urinary 

 papilla ; in the male it is 

 coiled and serves, as in 

 the frog, for the vas 

 deferens, its swollen 

 hinder part being a 

 vesicula seminalis. The 

 tubules of each meta- 

 nephros are received 

 into five or six ducts, 

 which in the female open 

 into the urinary sinus of 

 their side, but in the 

 male join to form a ureter 

 which passes backwards 

 to open separately from 

 the vesicula seminalis 

 into a median urino- 

 genital sinus. This has 

 two forward horns 

 known as the sperm 

 sacs, which lie upon the 

 ventral faces of the 

 vesiculae seminales, and 

 opens behind into the 

 cloaca by a urinogemtal 

 papilla behind the anus. 

 There is a single ovary, 



