452 DISSECTION OF THE PIGEON. 



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 

 in length. 



The egg, when discharged from the ovary, 

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

 albuminous substance formed romid 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 simila.r to that of the male, but larger. 



a. The rectum has the same relations as in the 



male. 



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



ureters are in 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. 



e. The posterior chamber is as in the male. 

 VIII. EXAMINATION OF THE BKAIN. 



A. Removal of the Brain. 



Cut through the skin of the top of the head along the 

 middle line, and turn the flaps aside. Expose and scrape 

 clean the bones of the roof of the skull. Slice off with a 

 scalpel the skull-roof, taking care not to injure the brain, 

 which lies very close to the bone. 



