rilla resembles
Man are those in which it differs from the Baboon; while various
respects in which it differs from Man are exaggerated in the
'Cynocephalus'. The number and the nature of the teeth remain the same
in the Baboon as in the Gorilla and in Man. But the pattern of the
Baboon's upper molars is quite different from that described above
(Figure 17), the canines are proportionally longer and more knife-like;
the anterior premolar in the lower jaw is specially modified; the
posterior molar of the lower jaw is still larger and more complex than
in the Gorilla.

Passing from the old-world Apes to those of the new world, we meet with
a change of much greater importance than any of these. In such a genus
as 'Cebus', for example (Figure 17), it will be found that while in
some secondary points, such as the projection of the canines and the
diastema, the resemblance to the great ape is preserved; in other and
most important respects, the dentition is extremely different. Instead
of 20 teeth in the milk set, there are 24: instead of 32 teeth in the
permanent set, there are 36, the false molars being increased from eight
to twelve. And in form, the crowns of the molars are very unlike those
of the Gorilla, and differ far more widely from the human pattern.

The Marmosets, on the other hand, exhibit the same number of teeth as
Man and the Gorilla; but, notwithstanding this, their dentition is very
different, for they have four more false molars, like the other American
monkeys--but as they have four fewer true molars, the total remains the
same. And passing from the American apes to the Lemurs, the dentition
becomes still more completely and essentially different from that of
the Gorilla. The incisors begin to vary both in number and in form. The
molars acquire, more and more, a many-pointed, insectivorous character,
and in one Genus, the Aye-Aye ('Cheiromys'), the canines disappear, and
the teeth completely simulate those of a Rodent (Figure 17).

Hence it is obvious that, greatly as the dentition of the highest Ape
differs from that of Man, it differs far more widely from that of the
lower and lowest Apes.

Whatever part of the animal fabric--whatever series of muscles, whatever
viscera might be selected for comparison--the result would be the
same--the lower Apes and the Gorilla would differ more than the Gorilla
and the Man. I cannot attempt in this place to follow out all these
comparisons in detail, and indeed it