154 ON THE classification OF BIRDS. 
sores with the Rasorcs, the hinder toe is nearly as long 
as in the cuckows, and is considerably more developed 
than in any other group of rasorial birds. We wUl say 
nothing of the genera Meyapodhis, Palamedia, and 
Menurn, whose feet are well known to be enonnous; or 
of Opisthoconius, because specimens of these large and 
rare birds are not upon our table. Confining ourselves 
to the genus Penelope, we may remark that the toes, 
considered by themselves, might be taken for those of a 
cuckow, if the outer one was only versatile ; it is evident 
also, from the structure of the claws, that these birds 
are much more arboreal than their congeners, for their 
claws are more curved ; and from their lateral, and not 
horizontal compression, as well as from their acuteness, 
we conclude that they are very little, if at all employed 
in scratching the ground, their structure being similar 
to those of perchers, and adapted only for clinging. The 
foot, in fact, of the Penelope is not a rasorial, but an 
insessorial foot, for it does not possess any one of the 
rasorial characters. Even the hind toe, which, in aU other 
rasorial birds, is raised above the lieel, is here placed 
upon the same len)el as the anterior toes {fig. 84.). That 
no ambiguity should rest on this fact, we beg to call the 
ornithologist’s attention to the particular species now 
before us, the P. aracuan of Spix (ii. pi. 74.), one of the 
most common of the genus. How this remarkable forma- 
