266 THE ANTIQUITY OF MAN 
is post-bregmatic in position, results from the great 
growth of that part of the brain which Hes under the 
parietal region of the vault. The parietal lobes of the 
human brain are known to be the seats of the higher 
functions of the brain. In the course of the evolution 
of the human brain these parietal association areas have 
undergone a great growth and expansion. Such a growth 
tends to raise the part of the vault under which the 
parietal areas are situated. We should expect these 
parietal association areas to be of relatively small develop- 
ment from a mere inspection of the Pithecanthropus 
skull. As a matter of fact, such is the case. Dr Dubois 
succeeded in taking a cast of the cavity of the skull. 
The cast showed very clearly the convolutionary pattern 
of the brain. He noted that in the region of the parietal 
association areas the brain was poorly developed. 
The forehead of Pithecanthropus shows many anthro- 
poid features. It is low and receding ; the orbits are 
crossed by a true simian bar of bone — the torus supra- 
orbitalis. This gorilla-like feature is one which also 
persists in Neanderthal man. The forehead is very 
narrow — only 84 mm. when measured between the 
temporal lines. In human skulls these lines diverge as 
they ascend on the frontal bones ; in anthropoid skulls 
they approach towards each other as they pass backwards 
on the vault. In Pithecanthropus the temporal lines 
run almost parallel with each other. This condition 
represents a developmental stage in young anthropoids. 
The minimum width of the forehead in Pithecanthropus, 
as we have seen, is 84 mm. — 10 to 20 mm. less than is 
common in modern skulls ; but as regards the width just 
above the orbits, the measurement is about the same as 
in modern skulls — 102 or 104 mm., nearly 20 mm. less 
than in the more robust Neanderthal skulls. 
In Pithecanthropus the head was attached to the neck 
exactly as in a young anthropoid ape (see figs. 90, 136). 
The occipital lines, which limit the area to which the 
muscles of the neck are attached, and which spread out on 
the skull as the muscles of the neck grow, almost reach 
