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. 

 ad^, abdominal pores ; c/, cloaca ; c/, ctaspers of the male ',_/] rudiment of the 

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

 od, oviduct; £e, cut end of ossophagus; o^, oviducal gland; 07', ovary; Pf, 

 pelvic fins ; R, rectum ; s..<:, sperm sacs ; T, testis ; m^, urinary i apilla in the 

 female ; tt£'/>, urogenital papilla in the male ; us, urinary sinus ; ve, vasa 

 efferentia; vs, vesicula seminalis ; IVZ>, Wolffian duct ; W^G^, Wolffian gland or 

 mesonephros. 



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

 only functional excretory organ of the female. 



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