Fig. 21.—Fœtus of an Orang. Exact copy of a photograph, showing the form of the ear at this early stage.
The following woodcut serves still further to show vestigial resemblances between the human ear and that of apes. The last two figures illustrate the general resemblance between the normal ear of fœtal man and the ear of an adult orang-outang. The other two figures on the lower line are intended to exhibit occasional modifications of the adult human ear, which approximate simian characters somewhat more closely than does the normal type. It will be observed that in their comparatively small lobes these ears resemble those of all the apes; and that while the outer margin of one is not unlike that of the Barbary ape, the outer margin of the other follows those of the chimpanzee and orang. Of course it would be easy to select individual human ears which present either of these characters in a more pronounced degree; but these ears have been chosen as models because they present both characters in conjunction. The upper row of figures likewise shows the close similarity of hair-tracts, and the direction of growth on the part of the hair itself, in cases where the human ear happens to be of an abnormally hirsute character. But this particular instance (which I do not think has been previously noticed) introduces us to the subject of hair, and hair-growth, in general.
Fig. 22.—Vestigial characters of human ears. Drawn from nature.
(8) Hair.—Adult man presents rudimentary hair over most parts of the body. Wallace has sought to draw a refined distinction between this vestigial coating and the useful coating of quadrumanous animals, in the absence of the former from the human back. But even this refined distinction does not hold. On the one hand, the comparatively hairless chimpanzee which died last year in the Zoological Gardens (T. calvus) was remarkably denuded over the back; and, on the other hand, men who present a considerable development of hair over the rest of their bodies present it also on their backs and shoulders. Again, in all men the rudimentary hair on the upper and lower arm is directed towards the elbow—a peculiarity which occurs nowhere else in the animal kingdom, with the exception of the anthropoid apes and a few American monkeys, where it presumably has to do with arboreal habits. For, when sitting in trees, the orang, as observed by Mr. Wallace, places its hands above its head with its elbows pointing downwards: the disposition of hair on the arms and fore-arms then has the effect of thatch in turning the rain. Again, I find that in all species of apes, monkeys, and baboons which I have examined (and they have been numerous), the hair on the backs of the hands and feet is continued as far as the first row of phalanges; but becomes scanty, or disappears altogether, on the second row; while it is invariably absent on the terminal row. I also find that the same peculiarity occurs in man. We all have rudimentary hair on the first row of phalanges, both of hands and feet: when present at all, it is more scanty on the second row; and in no case have I been able to find any on the terminal row. In all cases these peculiarities are congenital, and the total absence or partial presence of hair on the second phalanges is constant in different species of Quadrumana. For instance, it is entirely absent in all the chimpanzees, which I have examined, while scantily present in all the orangs. As in man, it occurs in a patch midway between the joints.
Fig. 23.—Hair-tracts on the arms and hands of Man, as compared with those on the arms and hands of Chimpanzee. Drawn from life.