214 



ZOOLOGY. 



wing, far out at sea following in the wake of vessels for 

 food, and breed in holes in the ground. The terns are 

 known by their very long, stout beaks. They lay from 

 one to three eggs in a hollow in the ground. They are 

 noisy, with shrill voices, and, like gulls, are gregarious. 

 The common tern or sea-swallow {Sterna hirundo) has a 

 red bill, while the roseate tern (£. paradiscea, Fig. 251) has 



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Fig. 252.— A, Kittiwake Gull; B, Ivory Gull. From Nordenskiold. 



a black bill, and the body is rosy beneath. The gull family 

 have larger bodies and feet, and the wings shorter than in 

 terns. They occur on all sea-coasts and inland lakes (Fig. 

 252). The skuas (Fig. 253) have habits like those of gulls. 

 The most notable member of the group of petrels is the 

 albatross {Diomedea exulans) of the Southern hemisphere. 

 Its wings expand more than three metres (nearly ten feet). 

 It lays a single egg 12 cm. long, and spends most of its life 



