58 ANIMAL LIFE PAST AND PRESENT. 



members of the group most interesting from our 

 present point of view. These birds frequent fresh 

 waters, and swim with the whole of the body sub- 

 merged, so that only the head and upper part^of the 



long and flexible neck are 

 exposed. In this position 

 they look not unlike snakes 

 swimming on the water, 

 when seen from a little dis- 

 tance. It does not appear 

 that any use of the wings is 

 made in swimming. The 

 Gulls and Petrels, in which 

 the hind toe of the foot is 



FIG. 18. Foot of Pelican. 



not included in the web, 



have longer legs than most swimming birds, and' the 

 legs themselves are placed nearer the middle of the 

 body. Since these birds depend mainly upon their 

 powers of flight for obtaining their food, most of them 

 only make use of the surface of the water, upon which 

 they float placidly, as a resting-place. 



The Divers, Auks, and Grebes are, with the exception 

 of the Penguins, those birds which appear to have been 

 most profoundly modified for a life in the water, being 

 equally at home both on and below its surface. In 

 these birds the short legs are placed so far back that 

 when on land the body is carried in a more or less 

 nearly erect position, as we may observe in the Guille- 

 mots and Puffins of our coasts. Although the legs 

 themselves are very short, yet the toes are elongated, 



