786 EVENING DISCOURSES. 
interlocking canines. Prof. Arthur Keith, on the other hand, has now made 
a new restoration of the skull to show that its brain capacity must have been 
larger than that of the average existing civilised man. He has also recon- 
structed the lower jaw to prove that its teeth were in all respects human, 
without any enlargement or interlocking of the canines. The results of the 
paleontologist are thus totally at variance with those of the human anatomist, 
and Hoanthropus cannot be discussed until the facts are settled. 
Fortunately, Mr. Dawson has continued his diggings during the past 
summer, and, on August 30, Father P. Teilhard, who was working with 
him, picked up the canine tooth which obviously belongs to the half of the 
mandible originally discovered. In shape it corresponds exactly with that of 
an ape, and its worn face shows that it worked upon the upper canine in the 
true ape-fashion. It only differs from the canine of my published restoration 
in being slightly smaller, more pointed, and a little more upright in the 
mouth. Hence, we have now definite proof that the front teeth of Hoanthropus 
resembled those of an ape, and my original determination is justified. 
It may next be questioned whether the ape-like mandible belongs to the 
skull. We can only state that its molar teeth are typically human, its muscle- 
markings are such as might be expected, and it was found in the gravel near 
to the skull. The probabilities are therefore in favour of its natural associa- 
tion. If so, it is reasonable to suppose that the skull will prove to be that 
of a very lowly kind, not that of a highly civilised man. I have accordingly - 
made a new study of the specimen with the special help of my colleague, 
Mr. W. P. Pycraft, and I find that the only alteration necessary in our 
original model is a very slight displacement of the occipital and right parietal 
bones which Prof. Elliot Smith pointed out to us when he made his first 
studies of the brain. Both behind and in front I correctly identified the 
internal groove for the upper longitudinal blood-sinus which marks the middle 
line of the roof of the skull; and the reason why my adjustment of the occiput 
was not exact at first is, that on the hinder part of the parietal region of the 
skull-roof I noticed a longitudinal ridge which I supposed to be truly median, 
while the extraordinarily unsymmetrical development of the brain seemed to 
have pushed the longitudinal sinus at that part slightly out of its normal 
place. The change, however, only opens the top part of the skull behind to 
an extent of three-quarters of an inch, and there are compensations elsewhere 
through the necessary readjustments, so the total brain-capacity remains nearly 
the same as that I originally stated, well within the range of the smallest 
human brains of the present day. I have submitted our new brain-cast to 
Prof. Elliot Smith, who will shortly describe it in a memoir for the Royal 
Society, and he permits me to add that he finds it, in all essential respects, 
correct. 
Hoanthropus may therefore be regarded as one of the links in the chain 
of the human race which has hitherto been missing, and we may proceed to 
consider what it means. A single isolated specimen cannot be said to prove 
much, but at any rate it admits several interesting suggestions. : 
In the first place, it must be remarked that Mr. Dawson’s careful researches 
have conclusively proved the minimum geological age of the fossil. It is 
certainly the oldest typically human skull ever found, for it cannot be of later 
date than the early part of the Pleistocene period. It therefore seems to show 
that Prof, Boyd Dawkins and Prof. Gaudry were right when they said, many 
years ago, that our knowledge of the evolution of the Tertiary mammalia 
prevented our expecting to find fully-developed man in any geological forma- 
tion earlier than the Pleistocene. In Hoanthropus we have a human being 
with a distinct remnant of ape-like ancestors in his jaws; and in the human 
mandible, probably of the same period, found near Heidelberg, we have a 
slightly more advanced stage with teeth which are distinctly human. When 
the Pliocene forerunners of these species are found, they will probably fall 
rather into the category of apes than of man. 
Next in connection with the remarks I have made about the evolution 
of the brain in mammals, it is interesting to notice that the brain of Hoan- 
thropus makes a much nearer approach to that of modern man than his face. 
It therefore appears that the excessive development of the brain preceded the 
