39 
here no strict physical necessity controls the de- 
signer and framer of the organs. As the roots sus- 
tain the trunks of most plants, so do the feet those 
of most animals. They are, amongst animals, not 
merely props to the body, but, to most tribes, these, 
or parts manifestly analogous, as wings and fins, are 
principal organs of locomotion. They are, in many 
classes, concurrent with teeth, as instruments of de- 
fence and offence. In every class there appears to 
be a designed division of the whole into at least two 
sub-classes, as, those with armed, and those with 
unarmed feet. These distinctions, in concurrence 
with the teeth, are indices of destination to parti- 
cular food. The concurrence serves to remove doubt 
as to destination, where each singly may be given 
to compensate for a deficiency of the other, either 
separately or in cooperation with other parts of the 
form or frame. The sloth, for example, without 
incisive or canine teeth, possesses powerful claws, 
used in struggling with assailants, rending bark and 
climbing stems of trees. The mouth of the wolf is 
less formidable in appearance than that of the tiger : 
his claws are less hooked, and they are not retrac- 
tile: but this small difference is abundantly com- 
pensated by the tight muscular bracing of his frame, 
and other conditions of organization which give him 
superior power to pursue his prey. Neither the 
lion or tiger, or any of the cat kind, with one ex- 
ception, chase and pursue their prey. They attack 
from ambush by a sudden and tremendous spring. 
Their descent from their leaps would be attended in 
D 4 
