368 QUADRUMANA. 



posterior to the auditory foramen is very considerable, the occipital por- 

 tion of the skull appearing as if drawn out ; so that the occipital foramen 

 is farther removed from the posterior projection of the cranium than in the 

 immature male, and its plane is less oblique. The muzzle projects in an 

 obliquely straight line from the interorbital space to the alveolar margin of 

 the upper incisor teeth, at an angle as acute as in the Baboons, and, to a 

 great extent, the face being produced anteriorly : hence the ascending ramus 

 of the lower jaw slopes backward, at a considerable angle ; the base of the 

 lower jaw is slightly convex from the posterior angle to the symphisis of 

 the chin. 



The supra-orbital ridges continued into each other, across the glabella, 

 form a sort of barrier between the cranium and the face, and, in a front 

 view, almost hide from sight the cranium, which falls back, and is de- 

 pressed behind them. 



The sutures of the frontal, temporal, parietal, and occipital bones are 

 all distinct and unobliterated. 



The skull of the adult male presents such extraordinary distinctive 

 characters, compared with that of the adult female, as, independently of 



its rarity, to render a figure of it (258) of 

 the highest importance. At the first 

 glance, it will be perceived, that it is 

 much shorter than that of the female; 

 it is, also, much broader, and has the 

 vertex higher and more vaulted. The 

 occiput is abruptly compressed, in- 

 stead of being elongated; and the 

 muzzle, instead of being greatly pro- 

 duced, and sloping in an obliquely 



I of aduit male cinmpa nz ee. straight line from the interorbital space, 



is abbreviated ; and its fall from the orbits to the alveolar margin of the 

 upper incisors is gently concave ; the interorbital space is prominent and 

 convex ; the orbits are large, and nearly circular ; and the supra-orbital 

 ridge is thick, bold, and greatly developed ; the zygomatic arch is thrown 

 over a very deep temporal cavity, for the lodgment of an enormous mass 

 of temporal muscle ; the temporal bones are remarkably convex, adding 

 to the great and singular breadth of the posterior and basal parts of the 

 skull. From the external angle of the supra-orbital ridge, as in the 

 female, a raised osseous boundary to the temporal muscle commences; 

 which, however, sinks immediately into a rugged line, sweeping over the 

 parietal bone to the occipital ridge, which is more conspicuous than in the 

 female, but still not boldly prominent : the rugged lines do not coalesce on 

 the vertex, but only approach each other, an inch intervening between them 

 where they approximate the closest : the nasal orifice is somewhat oval, 



