THE ELASMOBRANCH FISHES 231 



system is distinguished as the metanephros, and it forms 



Fig. 56 



A. Urogenital system of the female. B. Urogenital system of the male dogfish. 

 abp, abdominal pores ; cl, cloaca ; cp> claspers of the male ;f, rudiment of the 

 oviducal opening in the male; Md, metanephric ducts; mtn, metanephros; 

 od, oviduct ; ae, cut end of oesophagus ; 0g, oviducal gland ; ov, ovarjr ; Pf, 

 pelvic fins ; R, rectum ; s.s, sperm sacs ; Z 1 , testis ; /, urinary papilla in the 

 female ; ugp, urogenital papilla in the male ; us, urinary sinus ; ve, vasa 

 efferentia ;" 7>s, vesictila seminalis ; WD, Wolffian duct ; WG, Wolffian gland or 

 mesonephros. 



the chief excretory organ of the dogfish in fact, it is the 

 only functional excretory organ of the female. - 



