FIG. 16.--Sections of the skulls of Man and various Apes, drawn so as to
give the cerebral cavity the same length in each case, thereby
displaying the varying proportions of the facial bones. The line 'b'
indicates the plane of the tentorium, which separates the cerebrum from
the cerebellum; 'd', the axis of the occipital outlet of the skull. The
extent of cerebral cavity behind 'c', which is a perpendicular erected
on 'b' at the point where the tentorium is attached posteriorly,
indicates the degree to which the cerebrum overlaps the cerebellum--the
space occupied by which is roughly indicated by the dark shading. In
comparing these diagrams, it must be recollected, that figures on so
small a scale as these simply exemplify the statements in the text, the
proof of which is to be found in the objects themselves.

But if we consider the proportional size of the facial bones to the
skull proper only, the little 'Chrysothrix' (Fig. 16) differs very
widely from the Gorilla, and, in the same way, as Man does; while the
Baboons ('Cynocephalus', Fig. 16) exaggerate the gross proportions of
the muzzle of the great Anthropoid, so that its visage looks mild and
human by comparison with theirs. The difference between the Gorilla
and the Baboon is even greater than it appears at first sight; for the
great facial mass of the former is largely due to a downward development
of the jaws; an essentially human character, superadded upon that
almost purely forward, essentially brutal, development of the same
parts which characterizes the Baboon, and yet more remarkably
distinguishes the Lemur.

Similarly, the occipital foramen of 'Mycetes' (Fig. 16), and still more
of the Lemurs, is situated completely in the posterior face of the
skull, or as much further back than that of the Gorilla, as that of the
Gorilla is further back than that of Man; while, as if to render patent