208 ELEMENTS OF OENIXHOLOGT. 



may be feathery, as in the Toucans and Honey-eaters ; or it 

 may be a mere rudiment at the bottom of the mouth, as in the 

 Kingfisher and Pelican. Very rarely, as in the Bustard, a large 

 pouch may open beneath the front of the tongue and be capable 

 of much distension with air. 



The gullet, or cesophagus, is sometimes very capacious. It 

 may also have a special dilatation in front, called a crop or in- 

 gluvies, wherein food can be temporarily retained, and sometimes 

 macerated, before reaching the stomach. Sometimes, as in the 

 Pigeon, there may be a double crop, and it may furnish a mOky 

 secretion at the breeding-season. Birds of prey throw up the 

 indigestible parts of their food as " castings." Other birds throw 

 up part of their food to feed their young. The Hornbill will 

 throw up the lining of its stomach. 



At the lower end of the gullet is the digestive stomach or 

 proventriculus, which answers to that part of our own stomach 

 which is called the " cardia." It is richly supplied with 

 glands. 



The next segment of the alimentary canal is the gizzard, 

 which answers to that part of our stomach which is called the 

 "pylorus." It generally has very thick fleshy walls, with only 

 a small internal cavity provided with a horny lining. It is 

 into this cavity that birds swallow down stones, which when 

 brought to bear on food by contractions of the gizzard's very 

 muscular walls, act as teeth and grind the grains or other 

 hard substances fed upon. In birds that feed on food which 

 needs no grinding, the gizzard's walls are much thinner. 



The intestine is much shorter relatively than in us. In the 

 Toucan it is hardly twice as long as the bird's body and bill. 

 It generally consists, as in ourselves, of two parts : an anterior 

 small intestine, which is continued into a shorter part called the 

 large intestine. The foldings of the intestine vary in arrange- 

 ment, especially those of the small intestine, and these arrange- 

 ments distinguish certain groups of birds. There is but little 

 difference of capacity between the so-called " small " and 

 " large " intestine. The anterior part of the small intestine is 

 called the duodenum, and this part is disposed in a pretty con- 

 stant fold called the " duodenal fold." The hinder part of the 

 large intestine is called the rectum. The transition between 

 the small and the large intestine is usually marked by a pair of 

 hollow offshoots or diverticula, called the cceca. These may 

 be very small or very large or of moderate size. Instead of a 



