450 THE ANTIQUITY OF MAN 
If we examine the mandible of a modern Englishman 
from the same point of view the difference is very 
striking (fig. 167, B). The bony framework of the 
modern jaw has undergone a remarkable reduction. The 
bicondylar and bicoronoid widths have diminished, but 
not to a very marked extent. The masticatory area is 
greatly reduced. In the specimen represented in fig. 167, 
B, the dimensions are the following : length 5 1 mm., width 
(between outer margins of second molars) 60 mm. ; total 
area 2760 mm.^ If we presume that the mandible of 
Eoanthropus as restored by Dr Smith Woodward re- 
presents our ancestral condition at the beginning of the 
Pleistocene period, then during that period the length of 
the chewing area of the jaw has decreased 37 mm. 
(i| inches), the width only 4 mm., and the total area 
2120 mm.^ It will be observed that it is in length, not 
in width, that the chewing area of the mandible has 
decreased. In the Neanderthal race, at least, the width 
has actually increased. 
The modern English mandible represents an advanced 
stage in the process of reduction. For the purposes of 
comparison, it is better to select the mandible of a 
primitive race of the modern type, such as -may be found 
amongst the extinct Tasmanians. The palate of a Tas- 
manian native is represented in fig. 52 (p. 150), one in 
which the dimensions do not fall far short of those found 
in the palate of Eoanthropus. The length of the masti- 
catory area in the corresponding Tasmanian mandible is 
6t^ mm., the width 60 mm, ; the total area 3210 mm.-, 
against 3980 mm." in the writer's reconstruction of the 
Piltdown mandible, and 3540 mm.^ in the Heidelberg 
mandible. In the mandibles of very ancient man the 
chewing surface exceeds the highest modern develop- 
ment by a considerable amount. In the course of human 
evolution, the chewing area has become greatly reduced, 
a reduction which probably followed the growing mastery 
of the brain. The condition in Eoanthropus suggests that 
the brain had reached a volume equal to that of modern 
man before the reduction of the jaws and teeth set in. 
