286 



COMPARATIVE ZOOLOGY 



so that, in this respect, the crocodile may be considered 

 to be intermediate between reptiles and birds. 98 In 



crocodiles also 

 the duodenum, 

 with which the 

 intestine begins, 

 is first distinctly 

 defined. Into 

 this part of the 

 intestine the 

 liver and pan- 

 creas, or sweet- 

 bread, pour 

 their secretions. 

 Furthermore, in 

 the lower ani- 

 mals, the intes- 

 tines lie more 

 or less loose in 



the abdomen ; 

 -i . f-L. r^-r^r* 



odile, and like- 



wise in birds and mammals, they are supported by a 

 membrane called mesentery. 



In birds, the length of the alimentary canal varies 

 with their diet, being greatest in those living on grain 

 and fruit. The gullet corresponds in length with the 

 neck, which is longest in the long-legged tribes, and in 

 width with the food. In those that swallow large fish 

 entire, the gullet is dilatable, as in snakes. In nearly 

 all birds, the food is delayed in some cavity before 

 digestion : thus, the pelican has a bag under the lower 

 jaw, and the cormorant has a capacious gullet, where it 

 stores up fishes ; while those that gorge themselves at 

 intervals, as the vulture, or feed on seeds and grains, 



FIG. 247. Stomach of the Crocodile: a, muscular fibers ra- 

 dialing from a central tendon, b; d, commencement of 

 duodenum; c, esophagus; /, intestine. 



