The last group of the Scansores consists of those 
birds whicli are familiarly called Creepers {Certhiadc^ ^ 
from their habit of creeping about the boles and 
branches of trees, old walls, or other ruinous buildings. 
The members of this family are all climbers, but are 
separated from the preceding groups by the form of 
the feet, which instead of having the toes divided into 
pairs, have them disposed in the usual manner, that is, 
with three toes before and one behind ; their length 
and structure, however (particularly that of the hind 
toe), is such as to render them equally efficient in- 
struments for scaling perpendicular surfaces. In 
some species of the genus Dendrocolaptes, the bill is 
nearly the form of that of the Woodpeckers; and in 
others it is very con- 
siderably modified, in 
accordance with the 
peculiar habit of the 
species. The general 
form of the bill is, 
however, long and 
slender, and usually more or less curved downwards. 
For the structure of foot best adapted for running 
up the perpendicular surface of a wall or trunk of a 
tree we must look to the typical groups of the present 
family, and we shall find that the principal charac- 
