26 POULTRY DISEASES 



terv and occupies the space tetween the two large abdominal 

 air sacs. 



Large Intestine 



The large intestine is very short. At the point where the 

 small intestine terminates in the large intestine, there is 

 given off two long blind pouches — the ceca. These blind 

 pouches are directed toward the head. The ceca in pigeons 

 are comparatively short, while in fowls and ducks and geese 

 they are quite long. The major portion of the ceca is narrow, 

 becoming larger in calibre near the blind extremity. The 

 large intestine or colon extends backward in a straight line 

 with the under surface of the vertebrae and terminates in the 

 cloaca. 



The entire length of the alimentary tract in fowls is five 

 to six times, and in geese and ducks four to five times, the 

 length of the body. 



Cloaca 



The cloaca is a sacculation with greater diameter than the 

 large intestine and communicates anteriorly with the large 

 intestine and opens to the external world through the anus. 

 It receives the feces, urinary secretion and the eggs from 

 the oviduct in the female. The vas deferens of the male 

 opens through a papilla on the anal mucous membrane. At 

 the point where the rectum (large intestine) empties into 

 the cloaca, there is a strong, oblique fold of mucous mem- 

 brane. The ureters empty at the summit of small papillae 

 midway between the vasa deferens. The mouth of the oviduct 

 is a slit. In the males of ducks, geese and swans there is 

 present a copulatory organ, somewhat resembling the penis 

 of mammals. 



A small round or pear-shaped sac called the bursa of Fabri- 

 cus is located in the dorsal wall of the cloaca. The cavity 

 communicates, through a short canal, with the posterior bor- 

 der of the cloaca close to the anal wall. The mucous mem- 

 brane lining the bursa contains glands. The bursa is larger 

 in the young, but decreases in size with age. It apparently 

 reaches its greatest size in chickens at about four months of 

 age, at which time it may measure two to three centimeters 

 by one and one-half centimeters. By ten or eleven months 

 of age it has become quite rudimentary. Its function is not 

 kf\own. Glands similar to those of mammals are located in 



the intestines. 



Liver 



The liver is the largest gland in the body and consists of 

 two lobes— a right and a left. The right lobe is somewhat 



