MAN AND APES. 
131 
that we find the greatest resemblance to man in this respect. It 
is in the Grorilla that great bony crests (for muscular attach- 
ment), like those of a carnivorous animal, attain their maximum 
of development. (Plate XCV. fig. 2 s.) 
The relation of the face to the brain-case is shown by what 
is called the cranio-facial angle. This angle is estimated by 
comparing the direction of a line drawn parallel to the base of 
the skull with another line drawn from the front end of that 
base to the middle of the lower margin of the upper jaw. Stress 
has been laid on the difference existing between man and the 
Gforilla as to this angle. But it does not appear to be a really 
important character, since much difference exists with regard to 
this character in forms admitted by all to be closely related, 
such as the two Baboons — the Mandrill and the Chacma. 
There is one small cranial character, however, in which the 
Grorilla approaches man more nearly than does any other Pri- 
mate. This is the existence of a certain ridge (termed vaginal) 
on the under surface of the bone which encloses the internal 
ear. Another process of the same bone (called styloid) is, how- 
ever, developed more in accordance with man in one of the 
Baboons than in any other Primate, while of the latisternal 
apes it is not the Gforilla, but the Orang, which in this matter 
is the most human. 
The Gfibbons are more human than the Orang, Chimpanzee, 
or Gforilla, as to the preponderance of the brain-case of the 
skull over the bony face. But the smaller American monkeys 
exceed the Gfibbons in this respect, while the Squirrel Monkey 
exceeds even man himself. 
A striking feature in the human skull is the prominence of 
the inferior margin of the lower jaw in front ; i.e. the presence 
of a “ chin.” The feature is quite wanting in the Gforilla, as 
also in the Orang and Chimpanzee. A more or less developed 
“chin,” however, exists in the Siamang, although no other 
species of Gfibbons, and indeed no other ape or Lemur oid, shows 
us a similar condition. 
Another marked character of mpm’s skull is the projection 
and transverse convexity of the bones of the nose. This con- 
vexity is quite absent in the Chimpanzee and in most Gfibbons. 
In the Orang these bones are exceedingly small and flat, often 
even uniting into one bone, or with the adjoining jawbones, if 
indeed they are not altogether absent. 
In the Gforilla, on the other hand, they are slightly convex 
transversely at their upper part, so that here we seem to have 
evidence of the predominant affinity of the Gforilla to man. 
Further examination, however, shows that this character can 
have no such meaning, since a still more decided convexity is 
. found to exist in some Semnopitheci, and even in the lowest 
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