KENAL AND EEPEODUCTIVE SYSTEMS 



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median aperture, and become converted into the oviducts ; 

 the mesonephros is small and unimportant ; while the 

 metanephros and its ducts form the functional kidney and 

 ureters of the adult. 



In the male the pronephric ducts are rudimentary and 

 functionless ; the mesonephric tubules become connected with 

 the testis, and act as vasa efferentia, conveying the sperma- 

 tozoa to the mesonephric duct which acts as vas deferens. 

 The metanephros and metanephric ducts, as in the female, 

 become the functional kidney and ureters. 



TABLE SHOWINa THE EMEKYONIO AND ADULT CONDITIONS 03? THE KIDNBTS 

 AND THEIK DUCTS. 



A. The Female. 



1. The ovary, which is single, is an elongated, soft, lobu- 



lated mass, varying a good deal in size, but usually 

 about two or three inches long in specimens of the 

 size described. It lies in the abdominal cavity a little 

 to the right of the median plane, and is attached to 

 the dorsal wall by a narrow fold of peritoneum, which 

 is very readily torn. 



The surface of the ovary is tuberculated, owing 

 to the contained ova. 



2. The oviducts, which are formed from the pronephric or 



Miillerian ducts of .the embryo, are a pair of tubes 

 running along the dorsal wall of the abdominal cavity, 

 ventral to the kidneys, and not far from the median 

 plane. Their anterior ends curve inwards round the 

 sides of the oesophagus, and iinite immediately in 



