286 ON THE CLASSIFICATION OF BIRDS. 
it has some claim by the uncommon length of its legs 
and its perfectly terrestrial habits. We confess^ how- 
ever, that until a proper analysis of this family has been 
made, we shall by no means be satisfied that this is the 
true station of Gypogeranus, Its conspicuous and very 
remarkable crest, wdiich rises from the back of the head, 
and can be spread out like a fan, and its aptness for 
domestication, are all in favour of its being a rasorial 
type ; more particularly as crests are absolutely unknown 
in that of the grallatorial. It is barely possible that 
this perplexing form may prove to be the rasorial sub- 
genus either of Cathartes or VuUur; in which case the 
grallatorial genus of the Vulturid^H will be unknown, 
unless Neophron fills that station. Difficulties of this 
sort will always attend the determination of those com- 
paratively few groups in zoology, where the links in the 
chain are wide apart ; and these difficulties are increased 
where the requisite analysis has not been gone into. 
Gypogeranus is evidently a compound, both in structure 
and habits, of the vulture and the falcon ; and we can 
incur no risk in placing it as the most aberrant of the 
former, seeing that, without any reference to our theo- 
retical views of the .subject, such an intervening station 
has been assigned to it by all the most eminent writers. 
It must be remembered, also, that the very same objec- 
tions occur against placing this bird between the Strigidu 
.and the Dididre, as those we have intimated against 
considering it as the grallatorial type of the VuUuridce. 
(237.) The Faloonidas, or falcons, exhibit the per- 
fection of the order ; they are distinguished by a much 
shorter and sharper bill, more or less toothed, and by 
very acute and strongly curved talons. Their form, in 
general, is lighter, their flight more graceful, and their 
courage much greater, than what we see in the vultures : 
unlike these latter, also, they live almost exclusively 
upon animals which they themselves have killed, resort- 
ing only to carrion or dead game when pressed by ex- 
treme hunger. The geographic range of this family, 
as a whole, is universal ; for wherever other animals 
