698 



ELASMOBRANCHII. 



segmental ducts of the kidneys. They end in front by be- 

 coming continuous with the tubulus of the anterior persisting 

 segment of the mesonephros on each side, and unite behind to 



FIG. 392. DIAGRAM OF THE ARRANGEMENT OF THE URINOGENITAL ORGANS 



IN AN ADULT FEMALE ELASMOBRANCH. 



m.d. Miillerian duct ; w.d. Wolffian duct ; s.t. segmental tubes ; five of them are 

 represented with openings into the body cavity, the posterior segmental tubes form 

 the mesonephros ; ov. ovary. 



open by a common papilla into the cloaca. The mesonephric 

 duct receives the secretion of the anterior tubuli of the primitive 

 mesonephros. 



(3) The ureter which carries off the secretion of the kidney 

 proper or metanephros. It is represented in my diagram in its 

 most rare and differentiated condition as a single duct connected 

 with the posterior segmental tubes. 



(4) The segmental tubes (s.t) some of which retain their 



FIG. 393. 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; s.f. segmental tubes; two of them are represented with open- 

 ings into the body cavity; d. ureter; /. testis; nt. canal at the base of the testis; 

 VE. vasa efferentia; Ic. longitudinal canal of the Wolffian body. 



