80 
very widely from the Gorilla and, in the same way, as Man 
does; while the Baboons (Cynocephalus, Fig.17) 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 de- 
velopment of the jaws; an essentially human character, super- 
added 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. 17), and 
still more of the Lemurs, is situated completely in the pos- 
terior 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 the futility of the attempt 
to base any broad classificatory distinction on such a character, 
the same group of Platyrhine, or American monkeys, to which 
the Mycetes belongs, contains the Chrysothriz, whose occipital 
foramen is situated far more forward than in any other ape, 
and nearly approaches the position it holds in Man. 
Again, the Orang’s skull is as devoid of excessively de- 
veloped supraciliary prominences as a Man’s, though some 
varieties exhibit great crests elsewhere (see p. 41) ; and in 
some of the Cebine apes and in the Chrysothriz, the cranium 
is as smooth and rounded as that of Man himself. 
What is true of these leading characteristics of the skull, 
holds good, as may be imagined, of all minor features; so 
that for every constant difference between the Gorilla’s skull 
proportions of the facial bones. ‘The line d 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 perpen- 
dicular erected on } at the point where the tentorium is attached posteriorly, 
indicates the degree to which the cerebrum overlaps the cerebellum—the space 
oceupied 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. 
