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 featlters ; and, after ex- 
plaining the different series, and the names by wliich 
they are distinguished, illustrate our remarks by instances 
of the various fonns they assume, and the influence 
which they have on the manners and habits of the birds 
fespectively 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 
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. Sp.), which represents the 
outlines 01 botli, a a is the hvmernSy or hravMum, h h the 
ore-arm, or cubitus, and c c the carpus, or hand. This 
alter, in man and in quadrupeds, is divided into fingers, 
or claws ; but in birds, according to M. Cuvier, there 
