5 i6 



DEVELOPMENT OF ELASMOBRANCH FISHES. 



the Wolffian body, which pour their secretion into the Wolffian 

 duct, and a posterior group forming the kidney proper, which 

 are connected with the ureter. 



FIG. 9. 



DIAGRAM OF THE ARRANGEMENT OF THE URINOGENITAL ORGANS IN AN ADULT 

 MALE ELASMOBRANCH. 



m. d. rudiment of Miillerian duct; w. d. Wolffian duct, marked vd in front 

 and serving as vas deferens ; st. glandular tubuli ; two of them are represented 

 with openings into the body-cavity; d. ureter; /. testis; nt. central canal at 

 the base of the testis; VE. vasa efferentia; k. longitudinal canal of the 

 Wolffian body. 



In the male the following parts are present (woodcut 9) : 



(1) The Mullerian duct (md) t consisting of a small rudi- 

 ment attached to the liver representing the foremost end of the 

 oviduct of the female. 



(2) The Wolffian duct (w. d} which precisely corresponds to 

 the Wolffian duct of the female, but, in addition to functioning 

 as the duct of the Wolffian body, also acts as a vas deferens (vd). 

 In the adult male its foremost part has a very tortuous course. 



(3) The ureter (d), which has the same fundamental consti- 

 tution as in the female. 



(4) The segmental tubes (st). The posterior of these have 

 the same arrangement in both sexes, but in the male modifica- 

 tions take place in connection with the anterior ones to fit them 

 to act as transporters of the testicular products. 



Connected with the anterior ones there are present (i) the 

 vasa efferentia (VE), united on the one hand with (2) the central 

 canal in the base of the testis (nt), and on the other with the 



