THE STUDY OF HUMAN PREHISTORY 
he normally assumes a stooping posture, with the head 
and especially the jaws carried far forward, more nearly 
approaching that of four-legged creatures on the one 
hand and of very early man on the other. 
The characters of the lower jaw or mandible, though 
too numerous and often too technical for us to describe 
in detail, contain much information for the anthro- 
pologist. The hinge, or articulation, by which the lower 
jaw is attached to the 
skull differs widely 
both in individuals 
and in races, so that 
this single character 
can tellus al reat 
deal regarding the 
shape of the head of 
which it once formed 
apart. The presence 
or absence of a chin 
also. means very 
much. All modern 
and recent races of 
men have a_ chin, 
while the apes have 
none, their lower jaws 
sloping right back- 
ward from the front 
teeth. Here again, the 
further back eee Fic. 9. The skull, spinal column, and pelvis 
intO mans _ remote of man and gorilla compared. After Boule 
past, the less do we 
find his chin developed, until in some of the most ancient 
human skulls it is practically absent (Fig. 8). 
Just inside the point of the human chin, back of and 
below the roots of the front teeth, occurs a small projection 
bearing two points to which the main muscles controlling 
the tongue are attached. Instead of a projection, the 
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GORILLA 
