450 Mr. N. A. Vigors oji the Natural Affinities 



the deficiency, accompanied by a corresponding weakness of 

 the whole member, is real, and of sufficient consequence to de- 

 prive the bird of the means of using its legs and feet to advan- 

 tage. The force and powers of these parts are in fact trans- 

 ferred to the wings, which are thus endowed with a more than 

 usual share of strength, in order to afford the bird a more than 

 usual assistance in the aerial mode of seeking its food which it 

 is assigned by Nature. In the Buceros, on the other hand, the 

 gressorial feet are accompanied by a superior robustness, which 

 counterbalances their inferiority in form. And hence the family 

 may consistently maintain its station in the vicinity of the more 

 perfectly formed and typical groups of the Insessores, which 

 are now before us. The tendency, already observed, which 

 opposite points of the circle in which a series of affinities is 

 united have to approach each other, accounts for the resem- 

 blance here pointed out between these otherwise discordant 

 groups, and serves to explain the reason why the analogous 

 relation between them has been mistaken for a relation of affi- 

 nity by systematic writers, so far as to induce them to arrange 

 all the gressorial birds in one connected group. Besides the 

 genus Bucei'os, liinn., the protuberance on the bill of which 

 varies in almost every possible shape in which fancy can embody 

 it, the present family includes the Momotiis of M. Brisson, 

 which accords with the entire of that genus in its gressorial feet, 

 and with several species of it, as the genus now stands, in its 

 curved but somewhat shorter and more attenuated bill. 



The family of Loxiada, the extreme of the tribe of Coiiirostres, 

 exhibits a conformity to the groups we have just quitted, in the 

 strength and grossness of their bill. Inferior to them chiefly 

 in size, some species of the family may be observed to equal 

 even the Hornbills, allowance being made for their relative pro- 

 portions, in the extreme enlargement of this member. The 

 curved and serrated bill of the latter family, perceptibly shorten- 

 ing 



