Page:Popular Science Monthly Volume 34.djvu/190

178. With man alone the upper limb is exclusively a hand. The hinder limb condenses in itself all the locomotive function which it has till now shared within certain limits with the fore-limb, but which has nevertheless remained directly its essential attribute. Man thus seems to be the direct continuation of the first Eocene mammalia; if not of the marsupials that preceded them, the confirmation of a type that had been begun; and it does not appear very logical that his transformation should have been effected at the expense of a branch which appears collateral. The monkeys have been produced by an adaptation of the hinder limb to an arboreal life, the fore-limb remaining what it was; this is a deviation in some way from the axis of evolution, a deviation from the primitive type. From this primitive type have been detached on one side the ungulates through a metamorphosis of a fore-limb adapted to prehension into a limb adapted to running, and through a harmonic perfecting of the four limbs for the same purpose; on another side, the carnivores, whose four limbs have been set, together with the teeth, the jaw, and all the skull, into harmony with the necessities to which they were subjected and the mode of life and regimen they had adopted; and, on the third side, the monkeys, which, seeing the earth taken possession of by swift-footed herbivores and bloodthirsty carnivores, have taken refuge in the trees, or at least have flourished and maintained themselves there, and have consequently fitted their extremities to that special kind of life.

For men to be derived from monkeys through the disappearance of the accidental adaptation of the hind-limb to a function normally devolving on the fore-limb—that is, by returning toward their primitive arch-ancestral type—seems strange. But it is possible, for nature does not take the shortest roads. From the carnivores, terrestrial animals, have descended the pinnipeds, which by a reversionary adaptation have had their limbs atrophied, brought near the body in the shape of paddles, and made to perform the part of fins. But the most probable is generally the most simple. The hook which such an evolution of man or of one of his precursors would have made is useless. It seems more rational to conceive the perfect bipedal and two-handed type as descending from a type which we have already seen marked out in Eocene times, and constituting the fundamental original of the mammalia. We should then have to consider the simian branch as a collateral branch in which the evolution has not gone beyond what is exhibited in the recent and fossil anthropoids.

This hypothesis would solve some difficulties in anthropology that seem insurmountable. The lowest human races known to us are so near to the higher races in proportion to the distance that separates them from the monkeys, that we can consider the