Much stress is laid by some writers on the bald head of one ape and the parted hair on the head of another. These features cannot be relied upon as having any specific meaning, unless there are as many species as there are apes. Sometimes a specimen has no hair on the crown of the head, while another differs from it in this respect alone by having a suit of hair more or less dense; and yet in every other respect they are alike. Some of them have their hair growing almost down to the eyebrows, and all hairs appear to diverge from a common center, like the radii of a sphere; another of the same species may have the hair parted in the middle as neatly as if it had been combed; another may have it in wild disorder. The same thing is noticed in certain monkeys, and it is equally true of the human being. As a factor in classifying, it signifies nothing. It may be remarked that the _kulu_ is inclined to have but little hair upon the crown of the head. Between the two species there is a close alliance. The males differ more than the females. This is especially true in the structure of certain organs. The face of the young _ntyigo_ is free from hairs, but in the adult state there is in both sexes a tendency to the growth of a light down upon the cheeks. The color of the skin is not uniform in all parts of the body. This is especially true of the face. Some specimens have patches of dark color set in a lighter ground. Sometimes certain parts of the face are dark and other parts light. I have seen one specimen quite freckled. It is said by some that the skin is light in color when young, and becomes darker with age; but I find no reason to believe that such is the case. It is true that the skin darkens a few shades as the cuticle hardens, but there is no transition from one color to another, and this slight change of shade is chiefly on the exposed parts. The _kulu_ has a short, round face, much like that of a human. In early life it is quite free from hairs, but, like the other, a slight down appears with age. He has on his body a heavy suit of black hair. It is coarser and longer than that of the _ntyigo_. It is also inclined to wave, thus having a fluffy aspect. The color is jet black, except a small tuft of white about the base of the spine. I have seen two in which this tuft was perfectly black. The skin varies in color less than in the _ntyigo_, and the darker shades are seldom found. The eyes are a shade darker, and in both species the parts of the eye which are white in man are brown in them. But this gradually shades off into a yellow near the base of the optic nerve. As a rule, the _kulu_ has a clear, open visage, with a kindly expression. It is confiding and affectionate to a degree beyond any other animal. It is more intelligent than its _confrère_, and displays the faculty of reason almost like a human being.