But before the middle of the Eocene period this homogeneous group had begun to split up into main branches. And by the later Eocene times the particular branch to which man's ancestors belonged had reached, even in Europe, the stage of lemuroid creatures—four-handed and relatively small-brained animals, still retaining many traces of their connection with the ancestral horse-like and insectivore-like forms. These lemuroids were forestine, and, perhaps, nocturnal fruit-eaters. They lived among trees, which their hands were especially adapted for climbing.
In the lower Miocene times the lemuroids again must have split up into two main branches, that of the monkeys and of the lemurs. We find no trace of the monkeys in the remains of this age; but, as they were highly developed in the succeeding mid-Miocene period, they must have begun to be distinctly separated at least as early as this point of time. To the monkey branch, of course, the progenitors of man belonged.
By the epoch of the mid-Miocene deposits the monkey tribe had once more presumably subdivided itself into two or three minor groups, one of which was that of the anthropoid apes, while another was that of the supposed man-like animal who manufactured the earliest known split flints. The anthropoid apes remained true to the old semi-arboreal habits of the race, and retained their four hands. The man-like animal apparently took to the low-lying and open plains, perhaps hid in caves, and, though probably still in part frugivorous, eked out his livelihood by hunting. We may not unjustifiably picture him to ourselves as a tall and hairy creature, more or less erect, but with a slouching gait, black-faced and whiskered, with prominent prognathous muzzle, and large pointed canine teeth, those of each jaw fitting into an interspace in the opposite row. These teeth, as Mr. Darwin suggests, were used in the combats of the males. His forehead was no doubt low and retreating, with bony bosses underlying the shaggy eyebrows, which gave him a fierce expression, something like that of the gorilla. But already, in all likelihood, he had learned to walk habitually erect, and had begun to develop a human pelvis, as well as to carry his head more straight upon his shoulders. That some such an animal must then have existed seems to me an inevitable corollary from the general principles of evolution, and a natural inference from the analogy of other living genera. Moreover, we actually find rude works of art which occupy a position just midway between the undressed stone nut-cracker of the ape and the chipped weapons of palæolithic times. This creature, then, if he existed at all, was the real primitive man, and to apply that term to the cave-men or the drift-men is almost as absurd as to apply it to the civilized neolithic herdsmen.
The supposed Miocene ancestor of humanity must have been acquainted with the use of fire, and have been sufficiently intelligent to split rude flakes of flint. But his brain was no doubt about half-way