QUADBUPEDS. 
329 
foot can never be anything else than an instrument of loco- 
motion. In the Apes and Monkeys, the feet become 
hands ; all of them having a thumb set on a different line 
from the other toes, and susceptible of being opposed to 
Hands of 
a. Bat; b. Mole; c. Dolphin. 
them, -whereby the prehensile power is immensely increased, 
and the capabilities of the organ are greatly varied. 
In all these cases, all of the extremities are of the same 
form, but there are some in which the fore and hind feet 
differ from each other. Thus, in the Bats, while the hind 
feet have five short clawed toes, the fore ones have the first 
four fingers immensely lengthened, like the ribs of au um- 
brella, across which a delicate membrane is stretched, and 
thus the fore limbs become organs of flight. And in Man, 
who, by his organic nature, comes into this Class, the feet 
are merely fitted for walking, while the anterior extremi- 
ties, forming hands incomparably more delicate and more 
