NATATORES. 



the body, for the purpose of protecting the animals 

 from the effects of the water, upon which they usually 

 reside. Most of the species frequent the sea or its 

 coasts : they feed on fish, their fry, insects, vermes, 

 marine Crustacea, or mollusca. 



The Natatores may be readily arranged, in accord- 

 ance with the quinary and circular distribution of 

 animals, detected and so ably illustrated by the learned 

 author of Hora? Entomologies, into the following 

 groups or families, viz. 



f behind the -, rslightly com- ) 

 equilibrium [~g J pressed : J 

 [ greatly com- * 

 v. pressed : ) 



of the body; | . 



. ALCADJE. 



ivings short:- 



in, or near, the 

 equilibrium ; 

 wings long : 



rail united by a > 

 membrane : ) 



three ante- 

 rior only 

 united : 



PELECANID.E. 



simple : 



dentated: ANATID.E. 



The above arrangement of the two great divisions, 

 which may be termed tribes, is apparently consonant 

 to nature, and the circle returns into itself by means 

 of certain Ducks that approximate in their structure 

 towards the Divers. The birds of the first tribe are 

 almost exclusively pelagic, and use their short wings as 

 fins in swimming or diving, at which they are very expert : 

 those of the second gradually recede from the typical 

 form, become less pelagic, more capable of walking, 

 from the forward position of their legs, and possess 

 greater powers of flight ; while, on the other hand, 

 these faculties are gradually lost as we pass on through 



