456 DISSECTION OF THE PIGEON. 



anterior ends of the kidneys, alongside the iliac 

 veins. They have no physiological connection 

 with the kidneys. 



2. The reproductive system. 



a. The testes are a pair of oval bodies attached by a 



fold of peritoneum to the inner borders of the 

 anterior lobes of the kidneys, and lying in con- 

 tact with their ventral surfaces. 



b. The vasa deferentia emerge from the inner sides 



of the posterior ends of the testes, and run back 

 along the outer borders of the ureters as a pair 

 of sinuous tubes with opaque walls. 



Their hinder ends are dilated into small vesi- 

 culae seminales, which open into the cloaca. 



3. The cloaca is a shallow cup-like depression into which 



the rectum, ureters, and genital ducts open. 



a. The rectum opens in the ventral wall of the cloaca. 



Slit up the rectum along om. side, and note its opening into 

 the cloaca. 



b. The urino-genital pouch is a saccular diverticulum 



of the dorsal wall of the cloaca, separated from 

 the rectum by a transverse fold. The ureters 

 open into it dorsally and close to the middle 

 line ; and to their outer sides are the openings 

 of the vasa deferentia, on the apices of a pair of 

 small papillae. 



c. The posterior chamber of the cloaca is a thin-walled 



dilatation of the dorsal wall of the cloaca, behind 

 the urino-genital pouch, and close to the external 

 cloacal opening : into its dorsal surface a glan- 

 dular diverticulum, the bursa Fabricii, opens in 

 young birds, but is usually absent in the adult. 



