What are some examples that Darwin gives of species whose basic form of limbs is similar, but who have vastly different uses for them?
He says, "What can be more curious than that the hand of a man, formed for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and the wing of the bat, should all be constructed on the same pattern, and should include the same bones, in the same relative positions?"