298 ANSERES. COLYMBID^E. 



FAMILY II. COLYMBIM:. 



(Divers.) 



Much more exclusively aquatic than the Ducks, 

 the Family before us, as their name imports, are 

 remarkable for the readiness and frequency with 

 which they descend beneath the surface of the 

 water, and for the great length of time during 

 which they can remain immersed. They have the 

 beak narrow, straight, and sharp pointed; the 

 head small ; the wings short and hollow ; the legs, 

 placed very far behind, near the extremity of the 

 body, are flattened sidewise so as to present a thin 

 edge before and behind ; the toes armed with 

 broad flat nails. In one genus the toes are united 

 by a membrane, and there is a short tail ; in the 

 other two the toes are divided midway to the base, 

 but are margined with broad oval membranes, and 

 there is no vestige of a tail. The latter chiefly 

 affect fresh waters, the former reside upon the 

 ocean. 



The backward position of the feet in these 

 birds, while it renders them powerful and fleet 

 swimmers and divers, greatly diminishes their 

 ability for walking. Indeed they scarcely walk 

 at all, for though they can shuffle along awkwardly 

 in an erect position, it is only for a few steps, 

 when they fall down upon their breast, or else 

 remain sitting erect, supported upon their broad 

 feet as a base, the whole tarsus resting on the 

 ground. Their powers of flight are nearly as 

 limited : but under the surface of the water the 

 wings are expanded and used effectually as fins. 



