5 Pronephros 



Gonad 



Mesonephros 



Mullerian duct 



Mesonephric duct 



'Urinogenital sinus 

 [0 ^U.G.pore 

 G. papilla 



A. Cyclostome* 



R Undifferentiated 

 Dogfish Embryo 



Ostium 



vary 



viduct 



Epididymis 

 Testis 



Mesonephros 



Mesonephros 



—Mesonephric duct 



C. Female Dogfish 



D. Male Dogfish 



Fig. 144. Urinogenital System of Anamniotes. The Cyclostome condition 

 is shown in (A), the arrows indicating the course of the reproductive cells 

 from the gonads to the urinogenital pores. Drawing (B) is the undifferen- 

 tiated stage in the Fish and Amphibia, with the definitive structure of the 

 female (C) and the male (D). 



