340 ON THE CLASSIFICATION OF BIKDS. 
same time that they represent the perfection of the 
class of Bibos. 
(S770 The CuBTiPEOES^ as their name exjiresses, 
are an assemblage of short-footed families, much di- 
versified in general structure ; but having the toes so 
arranged as not to admit of their being habitually em- 
ployed in walking. The situation of the toes is either 
similar to those of the ordinary perchers, or in pairs ; 
in some few there are only three, and there are not 
wanting instances (as in the colies and swifts) wdiere all 
the four toes are placed forward. These minor differ- 
ences, joined to others which will be subsequently men- 
tioned, serve to characterise the three aberrant tribes 
composing the primary group ; namely, 1. The Scan- 
sores ; 2. The Tenuiroslres ; and 3. The Fissirostres. 
(278.) The Scansoreb are composed entirely of those 
families which habitually and invariably climb among 
trees ; and, in consequence of this habit, have their feet 
peculiarly constructed for the purpose. Sometimes the 
toes are placed in pairs ; that is, two before and two 
behind : sometimes one of the outer toes is nearly versa- 
tile, so that it can be almost brought forward, while in 
others the three anterior toes are in the ordinary direc- 
tion ; but in all these variations the hinder toe is 
remarkably developed, as in the nuthatch and creeper, 
for the obvious purpose of giving support to the body : 
the tarsus is always very short, and none of these birds 
possess either the conic bill or tlie terrestrial habits 
of the last tribe. The woodpeckers {Pieidcp), the par- 
rots {Psittacidip'), the toucans (Ramphastidcv), the 
cuckows {Cucn/idce), and the creepers {Certhiiidat), are 
the several families under which the whole of the scan- 
sorial, or climbing birds, are naturally arranged. 
(27,9-) The Tenuirostbes, or suctorial tribe, in- 
cludes the smallest and the most brilliant birds in creation. 
Unlike all others, they possess a long retractile tongue, 
jlivided into slender filaments, with wb.ich they lick the 
nectar of flowers. Many of them still retain something 
of file scansorial structure of the last tribe, particularly 
