“Thus, I suppose, they rest all night; and this posture accounts for some singular abrasions of hair on the side of the Nschiego Mbouvé. At a little distance off I saw another shelter made for the mate. No sooner was it seated than it began again to utter its call. It was answered; and I began to have the hope that I should shoot both animals, when an unlucky motion of one of my men roused the suspicions of the Ape in the tree. It began to prepare for descent, and, unwilling to risk the loss of this one, I fired. It fell to the ground dead. It proved to be a male, with the face and hands entirely black. As we were not in haste, I made my men cut down the trees which contained the nests of these Apes. I found them made precisely as I have before described, and as I have always found them, of long branches and leaves, laid one over the other very carefully and thickly, so as to render the structure capable of shedding off water. The branches were fastened to the tree in the middle of the structure by means of wild vines and creepers, which are so abundant in these forests. The projecting limb on which the Ape perched was about four feet long. There remains no doubt in my mind that these nests are made by the animal to protect it from the nightly rains. When the leaves begin to dry to that degree that the structure no longer throws off water, the owner builds a new shelter, and this happens generally once in ten or fifteen days. At this rate the Nschiego Mbouvé is an animal of no little industry.” The differences between the outside appearance and the intelligence and temper of this Bald-headed Ape and those of the Gorilla are accompanied by certain internal ones. A careful examination of the skull of the Tschiégo, as its clever French describer, Duvernay, calls it, shows that it has smaller ridges, a less prominent muzzle, and a wider and shorter roof of the mouth than the Gorilla. The last of the upper crushing, or back teeth, is the smallest. In the Gorilla they are nearly equal in size. The lower jaw in the Nschiego has three nearly equal-sized molar or back teeth, and the first and the second have five projections or cusps, but the last has only four. In the Gorilla it has five cusps. These minute differences are probably constant, and therefore must not be passed over, although they may seem to be of no importance to the creatures. But the classification of animals can only depend upon the presence or absence of structural peculiarities; and when such and such a structure exists in one, and not in another, they cannot both be of the same kind. According to the relation of the structure to the life, and according to its being constantly found, so is it important in deciding whether the “kind” is a species, or a mere variety or race. [Illustration: SKULL OF NSCHIEGO.]