The differences
between a Gorilla's skull and a Man's are truly immense (Fig. 16). In
the former, the face, formed largely by the massive jaw-bones,
predominates over the brain case, or cranium proper: in the latter, the
proportions of the two are reversed. In the Man, the occipital
foramen, through which passes the great nervous cord connecting the
brain with the nerves of the body, is placed just behind the centre of
the base of the skull, which thus becomes evenly balanced in the erect
posture; in the Gorilla, it lies in the posterior third of that base.
In the Man, the surface of the skull is comparatively smooth, and the
supraciliary ridges or brow prominences usually project but
little--while, in the Gorilla, vast crests are developed upon the
skull, and the brow ridges overhang, the cavernous orbits, like great
penthouses.
Sections of the skulls, however, show that some of the apparent defects
of the Gorilla's cranium arise, in fact, not so much from deficiency of
brain case as from excessive development of the parts of the face. The
cranial cavity is not ill-shaped, and the forehead is not truly
flattened or very retreating, its really well-formed curve being simply
disguised by the mass of bone which is built up against it (Fig.
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