﻿EXTERNAL ANATOMY. FEATHERS. WING. 79 



paragraph. Although similarly constructed, they are 

 eminently distinguished from the last by their great de- 

 velopment, and by that peculiar office they perform in 

 enabling the bird to mount in the air, and to direct its 

 voluntary course. They are much more diversified in 

 their size, form, and even structure, than the ordinary 

 feathers of the body, because they regulate all those 

 variations which we see in the flight of birds; and they 

 consequently form the basis, which the others do not, 

 of numerous and important systematic distinctions. We 

 shall first consider the wing feathers ; and, after ex- 

 plaining the different series, and the names by which 

 they are distinguished, illustrate our remarks by instances 

 of the various forms they assume, and the influence 

 which they have on the manners and habits of the birds 

 respectively possessing them. It is necessary, how- 

 ever, to the clear elucidation of these remarks, that 

 the reader should understand something, in the first 

 instance, of the bony structure of the wing of a bird, 

 that he may be able 

 more readily to know 

 the situations occupied 

 by the different series 

 of feathers with which 

 it is covered. 



(73.) The joints 

 of the wing correspond 

 with, and are analo- 

 gous to, those of man 

 and of quadrupeds ; 

 yet they are so singu- 

 larly modified, that 

 an ordinary observer 

 would not perceive 

 their mutual relation. 

 In the annexed cut (fig. 3Q.), which represents the 

 outlines of both, a a is the humerus, or brachium, b b the 

 fore-arm, or cubitus, and c c the carpus, or hand. This 

 latter, in man and in quadrupeds, is divided into fingers, 

 or claws ; but in birds, according to M. Cuvier, there 



