Conclusion 
3i 
minence of the bony brow, and the large size of the face. The 
skeleton of his trunk also exhibited a combination of more ape- 
like features than are known in any single human skeleton of 
later date. Still earlier Heidelberg man, though with typically 
human teeth, had a much more retreating bony chin suggestive of 
closer relationship to the apes. Finally, Piltdown man, who is 
at least as old as the Heidelberg race, and probably older, had 
both lower jaw and front teeth as nearly on the ape-pattern as 
was compatible with their working on a human skull of normal 
width. His skull, however, though with a very large face, and in 
some respects the most ape-like known, appears at first sight to 
be contrary to expectation in the steepness of its forehead and the 
absence of the modern ape's characteristic brow-ridges. But it 
must be remembered that, in accordance with a well-known law, 
the skull in the adult ancestral apes of Miocene times (still to 
be discovered) probably resembled that of the very young existing 
ape (fig. 5a, p. 15), not that of a full-grown individual (fig. 5b). 
Just as the bony brow-ridges are acquired during the life of each 
individual existing ape, so the race of apes began without them, 
and only gradually acquired them as an adult character through 
successive generations. The Piltdown skull, therefore, probably 
resembles the skull of the truly ancestral apes much more closely 
than does the later Neanderthal skull, in which the bony brow- 
ridges may be a mark of peculiar degeneration. It is possible that 
the earliest men were very varied, some inheriting one set of traits 
and tendencies from the lower animals, others another set. Some 
might thus progress directly towards the existing form of man, 
while others might revert in different ways to a condition which 
prevented survival in the struggle for life. 
Hence, although the facts are still very scanty, it is evident 
that the further human remains are traced back in geological 
time, the more marks they retain of an ape-like ancestry. They 
suggest a gradual approach to a primitive forest-animal with an 
overgrown brain, which was destined to begin a fundamentally 
new departure in organic evolution. 
