384 
THE ANTIQUITY OF MAN 
the left frontal lobe rests. The impress of the third or 
inferior frontal convolution is seen. Far in front of the 
fossa or impress for this convolution is seen the external 
angular process of the frontal. On the right-hand side 
of the figure is shown a corresponding section of the 
Gibraltar skull. The external angular process is in front 
of the third frontal convolution. If one could conceive 
a great increase in the bulk of the frontal lobes of the 
TORUS SUPRA offa- 
X 3^:^ r/iONTAL 
CHIMPANZEE 
GIBRALTAR 
Fig. 139. — Section across the anterior end of the left side of a chimpanzee's skull 
and the right side of the Gibraltar skull, to show the relationship of the 
external angular process to the third frontal convolution. 
chimpanzee's brain it is easy to see how the condition in 
the Gibraltar skull might be evolved from a simian 
arrangement. In fig. 140 the condition of parts in the 
Piltdown skull is contrasted with that of a modern 
specimen. The external angular process is less prominent 
in the Piltdown skull ; it is also situated rather further 
back, more directly over the third frontal convolution 
than in the modern skull. It is clear that as regards this 
relationship the Piltdown skull is the opposite of simian. 
As regards the development and relationships of the 
