But we must not fall into the error of supposing that the early progenitor of the whole Simian stock, including man, was identical with, or even closely resembled, any existing ape or monkey."
This expectation has hardly been fulfilled, but of late years the notion of a variety of the human race, geologically ancient, differing from any known in historic times, and with characters approaching the simian, has been supported by further discoveries.
On the other hand it does not follow necessarily from a theory of evolution of species that mankind must have descended from a single stock, for the hypothesis of development admits of the argument, that several simian species may have culminated in several races of man.
It has to be borne in mind that Linnaeus, plainly as he recognized the likeness of the higher simian and the human types, does not seem to have entertained the thought of accounting for this similarity by common descent.
The foreheads of these two skulls have an ape-like form, obvious on comparison with the simian skulls of the gorilla and other apes, and visible even in the smallscale figures in the Plate, fig.
5), bearing a certain resemblance in its proportions to the corresponding part of the simian skull.
At any rate, classing the Trinil skull as human, it may be described as tending towards the simian type more than any other known.