In the Baboons there is a curious condition of the first bone of the neck (the atlas, or first vertebra, on which the head rests). It is a massive ring of bone, down the centre of which the great nerve (spinal cord) of the spine passes, and it becomes stouter with age, and the central hole is all the smaller. It has a small spinous process, to which there is a muscular attachment, which tends to keep up the heavy skull and long nose. A good short back-bone, not over pliant, is necessary to the Baboon, and a provision is made in order to produce this; for the bodies of the vertebræ are found to be larger and longer as they are further down the spine. This is what occurs in man and in the Gibbons, but it is only slightly noticed in the higher Apes--the Troglodytes and Orangs. The Baboon may be said to have sometimes only eighteen back and loin vertebræ, and twelve or thirteen are rib-bearing, and the spines of these bones are strong and often expanded or flattened at their ends; moreover, the last spines project forwards and the others backwards. All this arrangement is especially ape-and animal-like, and refers to the strengthening of the muscles used in moving on all-fours. There is of course a tail to be considered, and in the shortest there are from five to eight bones, or modified vertebræ, and whether short or long, the muscles of the tail are all to be met with at its root. Such clever animals ought to have well-formed brains, and yet not so elaborately constructed as those of the Anthropomorpha, whose movements are more varied, and who can walk erect for a longer or shorter time. It is found that the brain of the Baboon, although less complicated, or rather less perfectly formed, than that of the Chimpanzee and Orang, is singularly like those of the Guenons and Macaques in the surface markings and convolutions, and, in fact, the brains of these animals agree in all essential points. The principal convolutions and fissures which are noticed in the Troglodytes exist, but the external perpendicular fissure is strongly marked, and all the little brain is covered by the cerebrum, or brain proper.