367 



Chapter XIV. 



THE SKELETON OF THE FOWL. 



Galhis bdnkiva, var. domesticus. 



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

 Yenient for study than that of the pigeon. The differences 

 between the two are of but slight 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 limbs, fitting it for flight and bipedal locomotion. 



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

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

 l)Oiies in thick type. 



I. THE AXIAL SKELETON. 



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

 skull 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 vertebrsB ; (3) the great length of 



