CLASSIFICATION OF BIRDS. 395 



very long shanks, and by the nakedness of their legs towards the 

 bottom an arrangement which makes them look as if mounted 

 on stilts ; and which is very favourable both to their rapidity 

 in running, and to their fording deep waters ; their toes are 

 long, and are in general slightly webbed (Fig. 207) ; their 



figure is usually slender ; and 

 the length of their neck is 

 such, that however high they 

 rise on their legs, they can, 

 without stooping, pick up 

 their food from the ground. 

 Some feed on vegetables, 

 others on aquatic Reptiles, 

 Mollusks, small Fish, &c. 



Among these are classed river and shore birds, such as Herons, 

 Cranes, Storks, Bitterns, Woodcocks, Ibises, Avocets, Fla- 

 mingoes, &c. 



VII. The NATATORES, palmated, or Swimming Birds, are 

 characterised by having their legs, which are of moderate 

 length, terminated by broad swimming paddles. These oars are 

 formed by the connection of the toes by a fold of the skin 

 (Fig. 190) ; and are generally placed very far back ; which 

 arrangement renders swimming easy, but walking difficult. We 

 may mention as examples of this group, the Auks and the Pen- 

 guins, whose wings are so short as to render them useless for 

 flight; the Petrels, Albatrosses, Gulls, and Sea-Swallows, which 

 have, on the contrary, long wings, and a powerful flight ; and the 

 Pelicans, Frigates, and Gannets, which are as well organised for 

 flight as the preceding, and which are remarkable for a more 

 complete palmation of the feet ; also, Swans, Geese, and Ducks, 

 whose beak is covered with a soft skin, instead of being protected 

 with horn. 



360. Of these orders, that of INSESSORES is probably to be 

 regarded as typical of the class ; since it presents, in the highest 

 degree, all those characters by which the whole group is distin- 

 guished, swiftness of flight, beauty of plumage, powers of song, 

 the small or moderate size of the body, and the high development 



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