INTESTINES IN BIRDS. 187 



Intestines. The pyloric orifice by which the gizzard com- 

 municates with the intestines has no sphincter. The intestines 

 are much shorter proportionately in birds than in mammals. 

 The intestinal canal varies in different birds from twice to five 

 times the length of the body. Here, however, considerable 

 anomalies appear, owing to the more varied form of the body, 

 and especially to the great diversities in the length of the 

 neck in birds as compared to mammals. In carnivorous birds 

 the intestines have the smallest proportional length ; in gallin- 

 aceous birds, and the order passeres, which feed on grains, the 

 intestines are proportionately longest ; in birds that live ex- 

 clusively on fish, the intestines are comparatively nearly as 

 long as in the gallinaceous birds. 



In all birds the distinction obtains between small and great 

 intestines, though the difference in the external aspect of the 

 great intestines as compared to the small is very slight. The 

 small intestines, as in mammals, are commonly longer than 

 the great. It is remarked, however, that in the ostrich the 

 great intestines are longer than the small. In the greater 

 number of birds the same description is applicable to the 

 situation, form, and structure of the intestines. The duodenum 

 begins near the termination of the gullet ; that is to say, the 

 entrance to the gizzard and the exit from it are close to each 

 other. Between these two openings, in the common fowl, and 

 in some other birds, there is a prominence which may have 

 the effect of preventing the food from escaping into the duo- 

 denum before the stomach-digestion is completed. The duo- 

 denum hangs loose in the common fowl towards the right 

 side of the abdomen, while the remaining portions of the 

 small intestines make turns and unite themselves to each 

 other. In birds, as a rule, the intestines are destitute of 

 valvulce conniventes. 



The gallinaceous birds are distinguished by their very long 



