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| 125 | THE EVOLUTION OF MAN |
In endeavouring to trace out the ancestry of Man, we must next proceed to the other members of the Primates, among which Pithecanthropus is by far the most human. Unfortunately, our knowledge of this creature rests on very fragmentary material, and is lamentably incomplete. We possess a cranial calotte, three teeth, and a femur; but that in all. The calotte is far from perfect, it has lost a great part of the glabellar region, and presents no trace of sutures. It is scaphocephalic, probably in consequence of premature synostosis, and is so far abnormal. Signs of a pathological condition are also presented by the femur, which has suffered from exostosis.
In the absence of sutures, and the consequent impossibility of determining the position of the bregma and lambda, it is dangerous to attempt any exact comparison of the characters presented by the cranial calotte: the elaborate measurements that have been based on the conjectural position of the bregma,, and on the inion, which cannot be regarded as a trustworthy point of reference, are useless and misleading. Yet, despite its defects, the calotte has furnished a surprisingly large amount of valuable information. Dr. Dubois has obtained a cast of interior which throws much light on the configuration of the brain; this presents simian as well as human characters, so far as can be judged from the description, which is not accompanied by figures.
The probable capacity of the original cranium has been estimated at 855 cubic centimetres; so many uncertainties, however, enter into the calculation that these figures cannot be regarded with much confidence. The actual capacity may have been slightly greater, but it is not likely to have been less.
If future discoveries should show that the estimated capacity is approximately correct and not far removed from the average for the species, then it would represent a true annectant stage between the cranial capacity of Man and that of the apes. This will be seen from the accompanying diagram. The first curve to the right represents the distribution of cranial capacity in a European race (Tyrolese men), the next in Australian aborigines (men), the third in Australian aborigines (women), the fourth is a purely hypothetical curve for Pithecanthropus, the fifth also hypothetical for the gorilla.
