THE FACE OF FOSSIL MAN 493 
(A-B and C-D in the above figures). In the orang 
(fig. 183) the muzzle projects 135 mm. in front of the 
ear-passage ; the forehead 78 mm. ; the amount of 
prognathism — the extent to which the muzzle projects in 
front of the forehead — is 57 mm. In the Tasmanian the 
prognathism is 10 mm. ; in the Piltdown skull it is not 
more than 5 mm. at the utmost. In the La Chapelle skull, 
notwithstanding the great jaws, there is really a degree 
of " retrognathism " — the muzzle projects about 12 mm. 
less than the forehead. Prognathism is a simian character, 
but it is one which was developed to only a slight extent 
in Eoanthropus. In spite of the pointed canine teeth 
and massive jaws the face of Eoanthropus was essentially 
human. 
In fig. 185 several other features of the skull and face 
of Eoanthropus are indicated. The zygomatic arch is 
situated at a lower position as regards the plane of 
orientation — the line A-B — than in human skulls of the 
modern type (fig. 182). In this respect Eoanthropus 
resembled Neanderthal man and anthropoid apes. In the 
reconstruction shown in fig. 185, the tip of the coronoid 
process is placed on a level with the lower border of the 
zygomatic arch — a position occupied by this process 
in figs. 182, 183, and 184. Further, the length and 
direction of the fibres of the temporal muscle, which are 
inserted to the coronoid process, are indicated by long 
stippled lines. The fibres of that muscle were no longer 
in the ancient types than in modern types of man. But 
as regards other muscles of mastication — the masseter and 
internal pterygoid — the case was different. In ancient 
man these muscles were very large. 
There is another and final test which may apply to the 
Piltdown skull — one which brings out some of its peculiar 
characters. In fig. 186 a series of skulls is shown, each 
cut open from front to back so as to expose the parts 
which form the base. The series is so arranged as to 
bring the external meatus of the ear on the same vertical 
zero line. Each specimen has been set on a corresponding 
horizontal plane, represented by the line A-B. 
