332 
OIV THE CLASSIFICATION OF BIRDS. 
seems not unlike that of the swifts : hut the position 
of the toes are very different ; the three anterior are 
very nearly of equal length, and sufficiently united at 
their base to keep them always close to each other, 
so that the sole becomes much broader than if the 
divisions were distinctly cleft ; the claws, as if to com- 
pensate for the brevity of the toes, are remarkably long, 
being two thirds the length of the toes themselves’. 
The Trocliilidce thus present a most curious analogy 
to the larks and wagtails, for although they never, by 
any chance, alight upon the ground, where the two 
latter genera alone reside, yet both may be character- 
ised as having the claws pre-eminently ileveloped. One 
could hardly have imagined that nature would have 
established so teautiful an analogy between two groups 
so diametrically opposite in all other respects, except that 
of having the longest and the most slender bills of their 
respective circles. The claws, however, of the Trochi- 
Ud(B are very much curved, broad, and remarkably 
acute, a conformation which is always found in birds 
w’hich from living only upon trees, have additional 
powers given them of clinging to the branches ; such, 
in fact, are the habits of these teautiful little creatures ■, 
they never are seen, like other birds, hopping from 
twig to twig : they are either upon the wing or seden- 
tary ; and, as their well curved claws enable them to 
take a firm hold on the convex surface of slender twigs, 
we have aiipliod the epithet of clinging to the peculiar 
foot tliey possess. 
(120.) A prehensile foot is possessed by those birds 
which, like the TrochilidcB, rarely, if ever, touch the 
ground ; yet they are continually wandering among 
branches in search of their food : hence they require 
great strength of limb, without the necessity of a 
lengthened tarsus. This structure we accordingly liml 
in the short legged-thrushes, {Bmchypodinm) the 
orioles ( Oriolinai), the caterpillar catchers {CeUepyrinee), 
the fruit eaters (Ampelido'), and several other groups. 
The foot of these birds very much resembles that of tlie 
