THE BONES. 



whereas the Sparrow has only nine of these neck joints, the 

 Swan has twenty- three, the advantages of which must be 

 evident to all who have observed the ease and grace with 

 which this stately bird turns its neck in every direction, or 

 buries its head in sleep beneath the soft down of its wings. 

 The Toucan, the bird with the large beak mentioned in 



The Toucan. 



p. 31, affords a still more curious instance of this power of 

 movement in. the neck, nestling its head so completely among 

 the feathers of its back, as entirely to conceal its enormous 

 beak, and nearly assume the appearance of a ball of feathers : 

 in which form, secured from all exposure to cold, it sleeps 

 through the night. The reason of this deviation from the 

 form of skeleton common to other animals is, that the stiffen- 

 ing or consolidation in the parts of the backbone is essential 

 in order to give strength and steadiness to the trunk in the 

 violent muscular motion required by the act of flying ; for in 

 those birds which do not fly> as the Ostrich and Emu, the 



