342 THE ANTIQUITY OF MAN 
When the outline of the occipital aspect of a modern 
skull is set in such a frame, it will be found that the 
left half of the occipital bone extends further outwards 
than the right half. In fig. 117 this normal asymmetry 
is exemplified. The vertical part of the left lambdoidal 
suture passes out beyond the left lateral line ; on the 
right side it falls short of that line. The left half of 
the occipital bone is the larger, because the corresponding 
part of the brain is the larger. The left hemisphere 
of the brain controls the right half of the body ; hence 
it is believed that the preponderance of the left occipital 
pole of the brain is connected with right-handedness.^ 
The occipital asymmetry is due to a specialisation of the 
two halves or hemispheres of the brain. There is the most 
indubitable evidence that the left occipital region of the 
Piltdown brain was larger than the right ; the impress 
of the cerebral lobes on the inner aspect of the occipital 
fragment leaves no doubt on this matter. 
The reader may naturally resent the introduction 
of so many technical details. I can only plead that 
the method employed is of the utmost importance ; 
it must be exact and logical if we are to obtain abiding 
results. It is into such a framework as has just been 
sketched that the Piltdown fragments must be fitted ; 
at every turn we shall be checked by our guiding lines. 
One other matter, however, must be mentioned. It is 
clear that the hinder aspect of the skull will alter as 
we raise or lower the front end of the skull. It is 
therefore necessary to fix a chief or zero horizontal 
line at the front part of the skull to correspond with that 
which crosses the hinder lower angles of the right and 
left parietal bones.^ The hinder horizontal line, it will 
be remembered, represents the lower limit of the 
cerebrum ; in the frontal region a similar line must 
be chosen — one to indicate the lower limits of the frontal 
lobe of the cerebrum. If the anterior part of the base 
of the skull is preserved, this is an easy matter, but in 
1 See Professor Elliot Smith, ylnaf. A?iz., 1907, vol. xxx. p. 574. 
2 See A. Kt.\\.\\,Joi/rfi. of Anat. and Physiol.^ 1910, vol. xliv. p. 251. 
