EXTEBNAI. ANATOMY. TOES. 
123 
external signs that may appear of its insect food lurking 
within. But although we thus distinguish the foot of 
the PicidtB, as pre-eminently scansorial, it must not he 
supposed that they are of the otily structure which is 
quite adapted for cUmhing. Inttnite and harmonious 
variety is the great principle which pervades the crea- 
tion, one result of which is the accomplishment of the 
same purpose by a great diversity of means. Thus we 
shall find, even in the Scansorial tribe, other modifi- 
cations of the foot admirably adapted for climbing, 
although the toes are in the same position as those ot 
ordinary birds. 
(113.) We now come to those few examples where 
all the four toes are placed forward ; these, as we have 
already intimated, are found 
in the swifts {Cypneius, fig. 
6'4., a), CoUes {Coitus, b.), 
and corvorants( Curio). We 
might ahnost have in- 
cluded the Ciiprimulgidat, or 
night-jars, in this list, for 
their hallux, or hinder toe 
{fig. 65. a), although incapable of being brought on a level 
with the others, is still placed so far forward, even as when 
seen in a dried specimen, that it seems inserted on the 
side of the foot, rather than behind the others. It has 
been mentioned by some writer, that these birds never 
perch, Uke others, across the branch of a tree, but 
always parallel with it; so that in such a position the 
hinder toe would have no power of acting like that 
of other birds. If this 
fact is correct, it favours 
the supposition that, when 
at rest, the hallux of the 
Caprimulgidai is placed for- 
ward, and that such is truly 
its natural position. Some 
of our field naturalists, who 
may be in the way of procuring a fresh specimen of the 
