422 DISSECTION OF THE PIGEON 



2. The reproductive system. 



a. The ovary. In the embryo a pair of ovaries are 



present, hut of these the right one disappears 

 during development, and the left alone persists. 

 This is a large irregular-shaped body, suspended in 

 a fold of peritoneum opposite, and partly in front 

 of, the anterior lobe of the left kidney. Numerous 

 ova in various stages of development project from 

 its surface. 



b. The oviducts. The left oviduct is a wide convoluted 



tube, thin-walled in front, thick behind, and 

 lying along the left side of the pelvic cavity. In 

 front it opens into the body-cavity by a long 

 oblique slit-like mouth, which is in close contact 

 with the ovary. Posteriorly it opens into the 

 cloaca. 



The right oviduct is rudimentary : it has the 

 form of a slender tube, opening behind into the 

 cloaca, and usually not more than half an inch ia 

 length. The egg, when discharged from the ovary, 

 consists of the ' yolk ' only : the ' white ' is an 

 albuminous substance formed round the yolk by 

 the walls of the middle portion of the oviduct ; 

 and the shell is secreted by the hindmost part of 

 the oviduct shortly before the egg is laid. 



3. The cloaca is similar to that of the male,^ but of larger 



size. 



a. The rectum has the same relations as in the 



male. 



b. The urino-genital pouch. The openings of the 



ureters are on the anterior wall of the pouch, 

 about an eighth of an inch apart. The openings 

 of the oviducts are to the outer sides of those of 

 the ureters, the opening of the left oviduct being 

 much larger than that of the rudimentary right 

 one. 



c. The posterior chamber is the same as in the male. 



