THE PILTDOWN MANDIBLE 445 
we could obtain any evidence which would definitely 
debar us from associating it with the skull. We must 
admit that the majority of the features enumerated are 
not such as we should have expected to find present in the 
authentic mandible ; on the other hand, there is not one 
which places the jaw out of court. We now proceed to 
review the evidence of another kind — proof presumptive 
in favour of the mandible and skull being parts of one 
individual. 
We have seen that in many features the Piltdown 
mandible resembles that of the chimpanzee. Let us, 
therefore, as in fig. 165, reconstruct it as if it were such, 
and see the result. In comparing lower jaws, we must 
select a definite plane on which all are arranged, so that 
our comparisons may be just. The plane selected here 
is the upper or chewing surfaces of the three molar 
teeth. In fig. 165 two mandibles have been set on that 
plane and viewed from above. When a chimpanzee's 
jaw is so examined it is seen that the teeth on each side, 
from the third molar behind to the canine in front, form 
a right and left series which are almost parallel ; the outer 
borders of the canine teeth are nearly as widely separated 
as the outer margins of the last molars. The two halves 
of the mandible of Eoanthropus have been given this 
parallel form in fig. 165, and at first we seem to have 
obtained a mandible of a reasonable shape with a close 
resemblance to that of an anthropoid. There is one 
point, however, in which this reconstruction appears 
to break the ordinary rules of jaw conformation — the 
right and left coronoid processes, to which the temporal 
muscles are attached, are almost as wide apart as the 
outer ends of the two condyles. In anthropoids, and 
particularly in human mandibles, the bicondylar width is 
greater than the bicoronoid — the measurements being 
made between the outer extremities of these processes. 
The mandible as reconstructed in fig. 165 could not be 
articulated to the Piltdown skull, for the mandible 
attached to that skull must have had a bicondylar width 
of at least 120 mm., and the bicoronoid width must have 
