That the progenitor of man was arboreal in his habits seems altogether probable. Darwin recognizes in the arrangement of the hair on the human forearm the strongest evidence on this point, so far as the actual body of man is concerned; the remaining and perhaps stronger evidence being derived from appearances recognized in the unborn child. He, who usually seems as though he could overlook nothing, seems to me to have overlooked a peculiarity which is even more strikingly suggestive of original arboreal habits. There is one set of muscles, and, so far as I know, one only, which the infant uses freely, while the adult scarcely uses them at all. I mean the muscles which separate the toes, and those, especially, which work the big toe. Very young children not only move the toes apart, so that the great toe and the little toe will be inclined to each other (in the plane of the sole) nearly ninety degrees, but also distinctly clutch with the toes. The habit has no relation to the child’s actual means of satisfying its wants. I have often thought that the child’s manner of clutching with its fingers is indicative of the former arboreal habits of the race, but it is not difficult to explain the action otherwise. The clutching movement of the toes, however, cannot be so explained. The child can neither bring food to its mouth in this way nor save itself from falling; and as the adult does not use the toes in this way the habit cannot be regarded as the first imperfect effort towards movements subsequently useful. In fact, the very circumstance that the movement is gradually disused shows that it is useless to the human child in the present condition of the race. In the very young gorilla the clutching motion of the toes is scarcely more marked than it is in a very young child; only in the gorilla the movement, being of use, is continued by the young, and is developed into that effective clutch with the feet which has been already described. Here we have another illustration of that divergency which, rather than either simple descent or ascent, characterizes the relationship between man and the anthropoid ape. In the growing gorilla a habit is more and more freely used, which is more and more completely given up by the child as he progresses towards maturity.