Moreover, besides these causes of growth there are those hidden ones which refer to sex, the old males acquiring a hideous aspect in our eyes, but lovely in those of the more comely female Miases, from the growth of long head ridges and the curious face pads. The bulk of the brain of an Orang is about one-half of that of a man of ordinary mind; and the brain itself, whilst it is higher in measurement than that of any of the Apes already mentioned, is long and flat in comparison with that of man. In front it tapers off slightly, and is not flat in front and below, for there the eye-cases or orbits, by projecting upwards, render the brain in their neighbourhood, as it were, excavated. As in the other Apes, the back of the brain is well developed, and the several parts distinguishable in man exist. One of the furrows so visible in the Troglodytes, which marks the side of the brain towards the back (the occipito-temporal), is scarcely in existence in the Orang. There is something very human in the appearance of the brain case in the young of both species of Orang. The back and sides have the peculiar “bumpy” look of those of the child; there are then no crests, and the brow ridges, extremely small, merge into a straightish forehead. The face looks long in front of the eyes, or orbits, and these are elliptical or oval, and approaching the circular in outline. The cheeks look wide even in the young ones; and it will be noticed that the bone of the upper jaw (superior maxillary bone) has a short projection, which joins the molar or cheek-bone at some distance from the jaw. There is a hole or holes under the orbit in man and in the Troglodytes which transmits a nerve to the face, and people who have tic-douloureux know where it is very well; this is close to the junction of the molar and jaw-bones in the Troglodytes, but in the Orang this junction is much further off the middle of the face. This causes the extra width to the cheeks. The bone there forms the surface upon which the curious pad of fat and skin rests, which gives such an ugly look to the face in the old ones, when all these parts have grown to excess. The young have milk teeth, and in the upper jaw the last crushing or molar tooth has large cusps behind and projecting inwards, and the incisor teeth are equal in size. In the lower jaw the incisors are grooved in front in a curious manner; and the great molar teeth with five cusps have a curiously wrinkled-looking surface. Underneath the skull looks long, and the hole for the spinal cord is much longer than broad, and the joints or condyles are distant from the front of it. The palate is broad and the nose cavity also, and there is a bony styloid process connected with the ear-bone.