THE BONES. 
43 
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 
THE TOUCAN. 
through the night. The reason for this deviation 
from the form of skeleton common to other animals 
is, that this stiffening or consolidation in the parts 
of the hack-hone, is essential, in order to give 
strength and steadiness to the trunk, in the violent 
muscular motion required by the act of flying; for 
