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Chapter XIV. 



THE SKELETON OF THE FOWL. 

 GaUvs hankiva, var. domesticus. 



The fowl's skeleton is, on account of its larger size, more con- 

 venient for study than that of the pigeon. The differences 

 between the two are of but shght importance, and the following 

 description will practically apply to either. 



The bird's skeleton consists essentially of the same parts 

 as the rabbit's, but presents certain special characteristics, of 

 which the more important are : (1) the great lightness of all 

 the bones, many of which contain large air-cavities ; (2) the 

 marked tendency of bones, primitively distinct, to fuse with 

 one another in the adult ; (3) the modifications in the hmb- 

 girdles and hmbs, fitting it for flight and bipedal locomotion. 



As in the case of the rabbit's skeleton, the names of the 

 membrane-bones are printed in italics, those of the cartilage- 

 bones in thick type. 



I. THE AYTAT, SKELETON. 



The axial skeleton, as in other vertebrates, is divisible into 

 skuU and vertebral column. 



A. The Vertebral Column. 



As compared with the rabbit's, the vertebral column of 

 the bird is distinguished by, (1) the great length and flexibility 

 of the neck, the cervical portion being nearly equal in length 

 to the whole of the rest of the column ; (2) the rigidity of the 

 thoracic and abdominal portions of the column, owing to the 

 fusion of their component vertebrae ; (3) the great length of 



A A 2 



