HEADS IN PROFILE 387 
In the latter skull the vault rises 88 mm., above the base 
line ; in Pithecanthropus the vault was very low, only 
74 mm, above the base line (fig. 144). The importance 
of the auricular height as an index of brain development 
is very apparent ; the more the brain expands, the larger 
it becomes, the more is the vault of the skull lifted above 
the base line. As regards height of vault, the Piltdown 
skull is in agreement with skulls of the modern type. 
Every well-planned experiment is instructive, and in 
this respect the one which my colleagues designed for me 
formed no exception. It will be seen from fig. 141 that 
my attempt to restore the forehead was a complete 
failure. In the original skull the upper part of the 
forehead is prominent, while the lower part, above the 
root of the nose, recedes, thus falling short of the 
conventional anterior limit — the 190-mm. line. The 
reconstruction shows exactly the opposite conditions, the 
total length of the skull being nearly 5 mm. more than it 
should have been. I made an unpardonable blunder in 
two respects. In the first place, I had concluded from 
the rather large size of the mastoid process — placed just 
behind the ear — that the fragments I had to put together 
were parts of a man's skull, and therefore gave the 
reconstructed skull the prominent eyebrow ridges of the 
male. If I had looked carefully, I should have seen that 
the area for the attachment of the neck in the skull I 
had to reconstruct (fig. 141) was small — a characteristic 
female mark, for the neck of a woman is more slender 
than that of a man. The contour of the boss on the 
frontal bone, too, should have wakened a suspicion of a 
forehead which was drawn inwards, not prominent, in 
the region of the eyebrows. 
This error again drew my attention to the reconstruc- 
tion of the Piltdown forehead. I was all along alive to 
the fact that we have as yet no means of drawing any 
accurate conclusion as to the shape of forehead from so 
small a fragment of it as was found by Mr Dawson at 
Piltdown, but I supposed, with a set of teeth and a 
mandible so well developed as those which belong to 
