The skull of this Baboon has a face occupying about half of it, and the brain case is much contracted behind and at the sides of the brows, and is flattened behind and above, so that the top of the head and eyes look pressed down. There is a ridge at the back of the skull extending from each ear-bone to a little knot at the back part of the occiput. All the back of the head is marked by the impression of the muscles of the back and neck, and the space for the jaw muscles is large on the side. Underneath, the skull is very long, there is the usual small space for the opening of the nostrils into the throat, and the palate is long and arched. In a specimen in the British Museum there is a little hook of bone on one of the small hones at the base of the skull (internal pterygoid bone), which is seen also in man, and it is for a tendon of a muscle to pass around, the use of the muscle being to render the soft palate tense. Why this should be so well grown in this Baboon, whose voice is no better than others, is certainly strange. The face is made broad near the eyes by the projecting cheek-bones, and the orbits are broad, not widely open, and they are separated, as in some of the other Baboons, by a part of the forehead bone (frontal), and the upper part of the nose bones (nasals). The nostril opening is very triangular, and on either side is the broad smaller surface of the upper jaw-bone. The front bone of the upper jaw is very projecting. One is struck with the huge chin of the lower jaw, and how slanting and comparatively small are the jowl ends of it. Evidently from the great breadth of the back of the lower jaw, and its roughness for muscular attachments, it is a very strong one, the narrow part in front which holds the teeth being well moved up and down, and side to side, in biting and masticating. Their hands are rather short, the fingers are black, and the third and fourth are of the same length; they are strong and hold well, the thumb, however, being of no very great assistance. CHAPTER IX. THE DOG-SHAPED MONKEYS (_concluded_). THE BABOONS. The Second Division of the Baboons--THE MANDRILL--Easily Distinguished from the rest--Peculiar Appearance and Colour of the Face--The Cheek-ridges--Noticed by the Ancients--Brutality of its Disposition--“Jerry” at the Surrey Gardens--Their Wild State--Anatomical Peculiarities--The Back-bone and Liver--THE DRILL--Distinguished from the Mandrill--Probable Antiquity of these Baboons--Theories of their Relationship to other Animals--THE BLACK BABOON--Its Locality and Description--Probably a Forest Ape--General Summary of the Dog-shaped Quadrumana and Classification of the Group. THE MANDRILL.[67]