Page:Popular Science Monthly Volume 42.djvu/464

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developed in the ugliest among them. The brain of the horse, nearest by virtue of its less rudimentary anterior lobe to that of the Primates, is rude, notwithstanding its well-formed convolutions, in comparison with that of the simians in general. Even the skull of the monkeys has something human, and reflects the interior cerebral organ. The brain has been evolved in all the branches of the tree of the mammalia, and at the end of some branches is elaborate in its convolutions, sometimes surpassing that of man in their richness. But in only one branch, that of the monkeys, does that exist from the beginning which gives the brain a special value, and causes them eventually to excel, whether the number of convolutions be equal or unequal.

We are amused with the monkeys, without remarking how marvelously they too are organized for their peculiar mode of life. We see them sporting, grimacing, swinging from one branch to another, and performing the most incredible feats of real acrobats. But we do not reflect that these habits, these necessities of their existence, are precisely what has given rise to the organ to which man owes most, after the brain—the hand. That hand, which by a curious aberration had in some of the marsupials abandoned the anterior for the posterior extremity, still occupies that extremity in the lemurians. In the monkeys it returns to take possession of its natural place of election, there to perfect itself gradually and to result in the incomparable apparatus which has caused Franklin to define man as "the maker of instruments."

The brain and its accompanying type of skull, the hand and its annexes the nails, are the characteristics which have produced the privileged situation of those animals which are correctly grouped together under the designation of the order of Primates. With some modifications in the proportions of the limbs to height and some accessory characteristics, their variants give place in them to divisions ranging from the lowest up to man. These divisions, whatever may be their relative value and their respective distances, are five: The lemurians—the monkeys of the New World, or the cebeans, from which the arctopithecans are sometimes separated; the monkeys of the Old World; tailed monkeys or pithecans; tailless or anthropoids; and man. A question which we had set before ourselves, and which had been much discussed in the Société d'Anthropologie, was whether the anthropoids of this list are nearer to the pithecan and cebean monkeys or to man. Shall we place in the same group monkeys and anthropoids or anthropoids and man? The question was then one of measuring in some way the interval between these anthropoids and man and comparing it with the subsequent intervals between the lower monkeys. From the result came the adoption of one or