CLASS AVES: ORDER SPHEJSTSCI. 



161 



with their flesh, for greater warmth during incubation. The 

 Puffin drives rabbits from their holes, or burrows to the 

 depth of two or three feet to lay its single egg, while the Auk 

 deposits its two eggs upon a rocky shelf in the side of a cliff 

 overhanging the sea. 



ORDER SPHENISCI. 



General Characteristics. The Penguin is half fish and 

 half bird in its habits. It has paddle- wings, with short, rigid, 

 scale-like feathers, disposed in regular order, and is incapable 

 of flight. Its bones are dense and heavy, with no apertures ior 



Fig. 275. 



Spheniscus demersus, Jackass Penguin 



the admission of air. It usually keeps near the land, but 

 seldom visits it, except for nesting. Whole companies then 

 sit erect along the shore, where they might easily be "mis- 

 taken for a party of choristers with surplices and black 

 gowns." The Penguin is confined to the colder regions of 

 the South,* as the Puffin and Auk are to those of the North. 



* The Patagonian Penguins are said to collect in such numbers at breeding-places 

 as to cover thirty or forty acres. The ground is laid out in squares for their nests, 



