THE SWDIMIKG, OR NATATORUL GROUP. 151 



for there are others in which the powers of 

 flight are wonderful, the water serving only as 

 a reservoir of food, which is snatched on or near 

 its surface, and as an occasional resting place, 

 the bird floating buoyantly, till it soars into the 

 air. As examples, we may adduce the terns, 

 the gulls, the albatross, the petrels, etc., birds 

 thickly plumed, and which, in pursuit of their 

 prey, make only slight plunges into the sea, 

 or skim it ofi" from the rolling waves, and sel- 

 dom settle, except for a few minutes. 



Between these extreme links in the chain 

 there are others of intermediate position, and 

 among them is the family comprising ducks, 

 swans, and geese. 



We shall not attempt to enter into an ana- 

 lysis of the numerous sub-divisions, of this 

 extensive family, (termed Anatidce,) but only 

 offer a few general observations. 



In the ducks, swans, and geese, the body 

 is more or less boat-shaped, and covered with 

 dense plumage, there being an under-layer of 

 down next the skin. The feathers repel the 

 water, which runs off" them. The legs are 

 placed considerably backwards, so as to render 

 the support of the anterior part of the body 

 apparently laborious, and from this cause and 



