REPRODUCTIVE SYSTEM. 



6i3 



occur in Mammals. The kid- 

 neys are metanephric in origin. 



The waste products, consisting for 

 the most part of urates, pass in 

 semi-solid form down the ureters 

 into the median compartment of the 

 cloaca. 



In front of each kidney, at the 

 base of the iliac vein, there lies a. 

 suprarenal body. 



Reproductive system. — 



The testes lie in front of the 

 kidneys. Like the ovary, they 

 increase in size at the breed- 

 ing season, and dwindle after- 



FlG. 269A. — Male urogeni- 

 tal organs of pigeon. 



T., testes ; V., base of inferior cloaca. 

 vena cava; S.R., suprarenal 

 bodies ; K., kidneys with three 



Fig. 269. — Female urogenital 

 organs of pigeon. 



K. , Kidney with three lobes ; w. , ureter ; 

 c/., cloaca; 071., ovary; od., oviduct; 

 f.t., funnel at end of oviduct ; r.r.od., 

 rudimentary right oviduct. 



wards ; the sexual period in birds 

 being much more narrowly limited 

 than in most other Vertebrates. 



The spermatozoa pass from the 

 testis into a vas deferens, which lies 

 to the outside of the corresponding 

 ureter. The vasa deferentia, slightly 

 convoluted when full of sperms, and 

 with a posterior swelling or sem- 

 inal vesicle, open separately into 

 the median compartment of the 



In the adult pigeon, and in most 



las'def^r-C'"^! birds > there is online ovary; that 

 vesicle ; ci., cloaca. of the right side usually atrophies 



