THE TEETH OF FOSSIL MAN 455 
78 mm, in Dr Smith Woodward's reconstruction, and 
70 mm. in the drawing shown in fig. 168, B. The 
difference in the canine tooth is also apparent. It is 
conical and pointed, with a back-to-front diameter of 
14*5 mm., in fig, 168, A ; it is blunt as in modern man, 
with a front-to-back diameter of 10 mm,, in fig, 168, B, 
The drawings also bring out another feature to which 
reference will have to be made. It will be observed, in 
the scale placed above the teeth (fig, 168), that the zero 
of the dental scale is placed between the second pre- 
molar and the first molar tooth. Behind the zero point 
lie the three molar teeth, concerned in grinding and 
pulverising the food ; in front of that point are the 
cutting teeth, five in number — two premolars, one 
canine, two incisors — concerned in biting off and in the 
initial breaking up of the food. The zero point is thus 
situated at the junction of two functional areas — the 
front and back — and lies in the most stationary or 
conservative part of the dental series of the group 
of animals to which man and the higher apes belong. 
If the molar teeth in the higher primates undergo 
a change, it is the last or third of the series which 
is first affected. In the actual reduction or increase of 
the front teeth, the canine is the centre of the change, 
but the movement of the series as a whole is towards or 
away from the zero point. As will be seen from fig, 168, 
A and B, there is no difference of opinion as regards the 
Piltdown mandible and teeth behind the zero point ; the 
difference concerns the parts which lie in front of the 
zero point. Whether we regard Eoanthropus as a 
direct ancestor of modern man, or a collateral stem 
which became extinct, we must suppose that the 
mandible represents a primitive human form, and that it is 
from such a form that our modern mandibles have been 
evolved. The changes required to convert a Piltdown 
mandible into one of the modern European type are 
represented diagrammatically in fig, 168, A and B. In 
front of the zero line there has been a reduction of over 
half an inch. Behind the zero point the degree of 
