282 



BRANCH CHORDATA 



scales. 1 When under water the wings act as paddles and the feet as rud- 

 ders. Penguins are gregarious, swimming in schools, and are seldom 

 seen on land except at the breeding season, when they go in great numbers 

 to their rookeries. The nests of grass and leaves may be under stones or 

 in caves or burrows. The male assists in incubating the two white or 

 greenish eggs, which require six weeks to hatch. The young are blind and 

 altricial, and are fed by the parents, which insert their bills in those of the 

 young. The food of the penguin consists of crustaceans, mollusks, and 

 fishes with a small amount of vegetable matter. The voice may be a 

 hoarse bark, " croak or scream, or a murmuring sound, or, in the young, it 

 may be a whistle." 



Order II. Longipen'nes. These are mostly sea birds, with long 

 wings and webbed feet. Gulls and terns may be named as ex- 



Fig. 230. Franklin gull; 15 inches. (Photographed from specimen.) 



amples of this order (Fig. 230). Gulls feed chiefly on fish, but 

 one may observe hundreds of them about an ocean liner as it 

 comes into port. They seek what is thrown overboard. They 



1 Hornaday. 



