NATATORES. 479 



ORDER VI. — NATATORES. Swimmers. 



Toes connected by membrane to the claws ; the feet fitted for 

 swimming ; lower part of the tibia usually feathered to near the 

 joint, which is bare ; hind toe, however, usually elevated, and rather 

 small, except in Pelecanidce ; fitted for an aquatic life, swimming 

 and diving freely ; rump with well-developed oil glands. 



The order Natatores, as characterized above, embraces a large 

 number of species of very varied forms, all more or less aquatic in 

 their habits. A character common to all consists in the presence 

 of a membrane between the toes, usually extending to the claws. 

 This membrane, when found in the GraUatores, is confined more 

 or less to the basal joint, unless Phanicopterus be an exception. 

 This genus has been variously placed in both orders, and it is still 

 a question where it really belongs. The internal anatomy resem- 

 bles that of the Natatores, as well as the lamellated bill and fully 

 webbed toes ; the external form however, as well as habits, bring 

 it nearer the GraUatores. 



The order Natatores of most authors has been divided by Bona- 

 .parte into two, — the Gavice and the Anseres : the former em- 

 bracing species which rear their young in nests, and belong to the 

 sub-class Altrices ; while the latter are Prcecoces, the young pro- 

 curing food for themselves almost from birth. 



Gavls:. — Bill without lamella?, and more or less entire ; feet 

 with the toes all connected by one continuous membrane ; or the 

 hind toe free, with the anterior continuously webbed. 



Anseres. — Bill with transverse lamella along the edges ; hind 

 toe free. 



