18 FORM AND HABIT; THE WING. 
tatus). The young of this bird have well-developed claws 
on the thumb and first finger, and long before they can 
fly they use them as aids in clambering about the bushes, 
very much as we may imagine the Archeopteryx did. 
In the adult these claws are wanting. 
Some eminently aquatic birds, as Grebes and Pen- 
guins, when on land, may use their wings as fore legs in 
scrambling awkwardly along ; while some flightless birds, 
for example, the Ostrich, spread their wings when run- 
ning. 
But let us consider the wing in its true office, that of 
an organ of flight, showing its range of variation, and 
finally its degradation into 
a flightless organ. Among - 
oy flying birds the spread 
Lat i wings measure in extent 
Fre. 5.—Short, rounded wing and large from about three inches in 
fet ind Ga) natural size)“ the smallest Hummingbird 
to twelve or fourteen feet 
in the Wandcring Albatross. The relation between 
shape of wing and style of flight is so close that if you 
show an ornithologist a bird’s wing he can generally 
tell you the character of its owner’s flight. The ex- 
tremes are shown by the short-winged ground birds, 
Fie. 6.—Long, pointed wing and small foot of Tree Swallow, an sérial bird. 
(3/, natural size.) 
such as: Rail, Quail, Grouse, certain Sparrows, etc., and 
long-winged birds, like the Swallows and Albatrosses. 
There is here a close and, for the ground-inhabiting 
