376 GENERAL ZOOLOGY 



Gulls and Terns. The group Longipen'nes (Lat. longus, 

 long ; penna, feather) includes long-winged water-birds with 

 sharply pointed or hooked beaks. The colors are usually gray 

 above and lighter below. The three front toes are connected 

 by a web. These birds are strong and graceful fliers, and 

 spend much of their time on the wing. All the members of 

 the group are gregarious, occupying nesting sites on sandy 

 beaches, in marshes, or on rocky shores. They obtain the 

 greater part of their food from the ocean, and are useful as 

 scavengers. Terns (Fig. 193) may be distinguished from 

 gulls by their usually deeply forked tail and straight bill. 

 Gulls are generally pelagic, and they often follow ships for 

 the sake of the refuse thrown overboard ; terns frequent 

 the shores of both fresh and salt water. Owing to the 

 forked tail and graceful flight, the terns are often called 

 sea-swallows. 



Petrels and Allies. The petrels and their allies are strong- 

 winged pelagic birds, many of which externally resemble the 

 gulls and terns. They may be distinguished from other water- 

 birds by the nostrils, which are inclosed in tubes lying on 

 the dorsal or lateral surface of the upper mandible ; hence 

 their scientific name, Tubina'res (Lat. tubus, tube ; naris, 

 nostril). The beak is usually strongly and sharply hooked. 

 The food consists of fishes and other small animals which 

 live near the surface of the ocean. The birds often follow 

 ships, like the gulls, to pick up refuse. They occupy various 

 nesting sites along shores. The wandering albatross (Dio- 

 mede'a ex'ulans) of southern oceans is the best-known species. 

 It is the largest of sea-birds, measuring over twelve feet 

 between the tips of the wings. One of the traditions among 

 sailors concerning the albatross is referred to in Coleridge's 

 Ancient Mariner. Other members of the group, called stormy 

 petrels and Mother Carey's chickens, are also regarded by 

 many sailors with superstitious dread. 



