378 
THE ANTIQUITY OF MAN 
If we used the inio-glabellar base line we should infer that 
the brain of the adult was much smaller than that of the 
young. The same change occurs, but in a less degree, in 
human skulls. Hence we must look for a more fixed 
base than that supplied by the inion and glabella. 
Ultimately the base line which I selected was one 
which roughly corresponds with the lower margin of the 
cerebrum or brain proper. It is plain that the secret we 
wish to wrinij from such fragments of skulls as 
wring 
may 
GLABELLA 
Fig. 136. — Profile of the skull of a chimpanzee to show the plane of 
orientation. The outline of the brain chamber is stippled. 
come to light is the kind of brain they enclosed. Our 
methods should therefore be framed with that object in 
view. Now the hinder lower angle of the parietal bone 
is a wonderfully persistent part of the skull. To that 
angle is attached the horizontal partition which separates 
the cerebrum above from the cerebellum below, not 
only in man, but in all animals allied to man. The 
posterior inferior angle of the parietal — the " asterion " 
as the point is named — is one which will serve well the 
purposes of a standard or base line for the hinder end of 
