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
Chrysothrix, 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 developed
supraciliary prominences as a Man's, though some varieties exhibit
great crests elsewhere (See pp. 231, 232); and in some of the Cebine
apes and in the 'Chrysothrix', 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 and the Man's, a similar
constant difference of the same order (that is to say, consisting in
excess or defect of the same quality) may be found between the
Gorilla's skull and that of some other ape. So that, for the skull, no
less than for the skeleton in general, the proposition holds good, that
the differences between Man and the Gorilla are of smaller value than
those between the Gorilla and some other Apes.

In connection with the skull, I may speak of the teeth--organs which
have a peculiar classificatory value, and whose resemblances and
differences of number, form, and succession, taken as a whole, are
usually regarded as more trustworthy indicators of affinity than any
others.

FIG. 17.--Lateral views, of the same length, of the upper jaws of
various Primates. 'i', incisors; 'c', canines' 'pm', premolars; 'm',