42 
THE BONES. 
who has given the best account of those regions, 
says, that he has frequently seen this enormous bird 
soaring without an effort, and enjoying itself at an 
elevation much higher than that of the clouds 
in our atmosphere. 
In tracing the bones of the skeleton down the 
back, another remarkable difference is perceptible. 
In men and animals, the whole back-bone is more or 
less moveable, and can be bent ; whereas, in birds, 
the parts more immediately connected with the 
back, are either altogether consolidated or stiffened, 
so as to allow little or no play in the joints. In 
carving a fowl or any other bird at table, this pecu- 
liarity may easily be remarked. The want of 
motion in the back, however, is amply compensated 
by a greater number of bones in the neck, and 
greater power of moving them, which enables birds 
to turn their heads in all directions, with extra- 
ordinary facility. These joints vary in number 
according to the necessities of the bird ; — thus, the 
Sparrow, which can perch and reach his food close 
before him, does not require such pliability, or 
length of neck as the Swan, which floats on the 
water, and must seek its food at a considerable 
depth beneath ; accordingly, we find, that, 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, men- 
tioned in p. 36, affords a still more curious instance 
