CHAP tie kh. ake, 
THE SEA-BIRDS. 
BIRDS are children of the air, just as fishes are of the water; yet 
there are many of the feathery tribes which ought to have a place 
amongst the creatures of the ocean, seeing that they live upon the 
water as much as they do in the air. The sea-birds are said to be 
one-fourteenth part of the whole bird family ; a family which can 
number 9,400 species. 
Since aquatic birds generally have their toes connected by a 
THE TWO KINDS OF WEB FEET. 
thin web, or skin, they are said to be web-footed. Nearly all the 
marine species are thus distinguished. Generally only three of the 
four claws are connected by the web, as in the case of the duck; 
but sometimes the skin extends to the fourth claw; this formation 
is exhibited in the cormorant. 
A glance at our illustration of these two kinds of web feet, 
will show that the latter form is the more powerful oar. These 
natural oars are greatly superior to the blades by which we propel 
our boats, for they need not be lifted out of the water to repeat the 
stroke. When the leg has reached its furthest stretch, the foot 
collapses, and is thus brought forward without offering any resist- 
ance to the water, and again spreads out to make another stroke. 
