CHAPTER IX. 



THE UEO-GENITAL SYSTEM. 



The Wolffian Body or Meso-nephros. — In lower vertebrates 

 (Fishes and Amphibians) the Wolffian body is the functional 

 kidney ; in higher vertebrates (Eeptile, Birds, and Mammals) it is 



tubules of 

 pro-nephros 



Wolffian duct- 

 Wolf, genit. tubules 



Wolf, renal tubules, 



pening into coelom 

 glomerulus 



genital gland 



glomerulus 

 meso-nephros 



Wolffian duct. 



allantois^\^y>y=^=d--^rectum 

 -cloaca 



Pio. 79.— Scheme of the Wolffian Body of the right side. 



merely a temporary or embryonic structure, the renal function 

 being taken over by the permanent kidney. Nothing is known 

 of how or when the permanent kidney arose and supplanted the 



