262 THE ANTIQUITY OF MAN 
is made manifest by the fact that their transverse (cheek- 
tongue) diameter is absolutely and relatively great as 
reofards the lone diameter. In simian teeth the length 
exceeds the width of the crown. In some minor features 
there is a resemblance to the molar teeth of the orang. 
The upper wisdom tooth (third molar), although of great 
size, being 15 mm. in width by 11-3 in length (the 
corresponding diameters in a native Tasmanian are 
i2XiO"5), yet shows a manifest reduction in develop- 
ment. The two posterior cusps have become reduced 
to form a crenulated, hinder margin on the crown 
instead of distinct cusps. As to the development of 
the canine teeth, a guarded statement must be made. 
The temporal ridges on the skull, being only slightly 
developed — as compared with their condition in the skulls 
of anthropoid apes — suggest small temporal muscles and 
canine teeth reduced to human dimensions. It will be 
seen in a subsequent chapter that I applied a similar 
process of reasoning to the skull found by Mr Charles 
Dawson at Piltdown. The subsequent discovery of a 
pointed canine tooth, which apparently belongs to the 
same individual as the skull, showed that this line of 
reasoning cannot be relied upon. 
If in build of body and form of teeth Pithecanthropus 
possessed just those features one would postulate for a 
primitive form of man, it is otherwise as regards the 
skull. When closely examined, its simian rather than 
its human characters are forced on our attention. In 
fig. 90 the Trinil calvaria is placed within the standard 
frame in which skulls of the modern human type have 
been set. As regards length, it falls well within the 
range of human dimensions, being only 5 mm. short of 
the mean for modern man. When we analyse the 
various elements which go to make up the length of the 
skull — the length of the brain and the thickness of the 
supra-orbital wall in front, the occipital wall behind — we 
see that the proportion of bone* to brain is much greater 
in Pithecanthropus than in modern man. His brain 
cavity measured 155 mm. in length, the supra-orbital 
