THE LIVING WORLD. 
397 
species that not only find their subsistence about the water, but which make the 
water a part of their natural element, swimming, diving, floating and disport¬ 
ing themselves among the waves with the grace 
and naturalness of fishes. In these birds we ob¬ 
serve wonderful provisions, specially adapting 
them to the life nature has designed them to lead. 
We find that while the waders have long legs, 
and toes well spread to give them firm footing, 
those that swim have short legs and webbed feet, 
and that the legs are placed well towards the tail, 
because this affords an increase of leverage in the 
act of propulsion. We also notice that swim¬ 
ming birds are provided with a very thick coat 
of feathers, which greatly increases their buoy¬ 
ancy, and that these feathers are covered with an 
oily substance which exudes from the root of 
the feathers, and that this natural supply is sultan hen. 
increased at the pleasure of the bird by an ex¬ 
traction from the excretory oil-duct that is- 
situated on the bird’s rump. In many 
species this oily exudation is so great as to 
render the feathers unfit for human use, 
but in all such cases we find that the sup¬ 
ply is necessary because such birds spend 
nearly all their time in the water. This oil 
not only renders the feathers impervious to 
water but also contributes greatly to the 
warmth of the bird, as well as enabling it 
to move with greater ease through the water. 
We shall also find that each species is 
specially provided with means for taking the 
food upon which nature intended that it should 
subsist. If it be appointed to take its prey 
during flight the wings are expansive and strong; 
if it lives upon prey taken beneath the water it 
is fitted for diving at the expense of flight; if 
it be designed to fish in the sea or seize its 
prey in the air, then nature has abundantly 
qualified it by special provisions of beak, claw 
and the means "for swift progression through 
the water. All these wonderful attributes will 
clearly appear in the descriptions following. 
The first species we shall consider is the 
Goose, omitting mention of the domestic spe- 
i, with which every one is supposed to be 
WATER RAIL. 
cies 
pee-wit ( Vanellus cristatus). 
acquainted, and particularly because it was from 
the wild varieties that our present domestic 
geese and ducks descended. There are nearly fifty different species of geese, 
found very widely distributed, but all essentially have the same habits and a. 
general description may therefore be applicable to all. 
