.4(58 SWIMMING BIRDS. 



teeth, the tongue is broad and fleshy, and toothed at 

 the margin. The wings are of moderate length. 

 These birds are inhabitants of fresh water rather 

 than of the sea. 



The Bucks (Anatidse). This extensive genus comprises all birds 

 having their beak large, broad, and furnished at the edges with 



FlG. 397. 'THE WILD DUCK. 



the prominent ridges above mentioned, which allow the water to 

 escape when the bird has seized its food. The Swans (Cyynus), 

 the Geese (Anser), and the true Ducks (Anas), are all included 

 under the same general appellation. 



Few circumstances in the history of these aquatic 

 races are more wonderful than their periodical mi- 

 grations. The Wild Geese, guided by an unseen 

 power, seek in spring the wild regions of the north, 

 in companies disposed in regular phalanx. During 

 the whole journey the most perfect order prevails. 

 The conducting of the troop is confided to a chief, 

 placed at the head of two files, more or less diverging, 

 but always meeting at a point. The chief, placed at 

 the apex of this moving angle, opposes the first 

 resistance to the air; he clears the way, and the 



