ANATOMICAL PECULIARITIES 153 
type the hinder part of the socket — the glenoid fossa — 
is deep, being excavated to the depth of the roof of the 
ear-passage. The front part of the articular platform 
has become developed as in the gorilla, forming an 
articular eminence in front of the socket. It is only the 
hinder or prae-auricular part of the anthropoid articular 
platform which remains undeveloped, giving rise to the 
well-known socket for the jaw — the glenoid cavity. 
When the condition of parts in the Gibraltar skull — 
representing the Neanderthal type — is examined, it is 
seen that the resemblance is much closer to the anthropoid 
than to the form found in the modern types of man. In 
this region of the skull Neanderthal man shows distinctly 
simian traits. So, too, in the passage of the ear. The 
plate of bone which forms the floor of the passage — the 
tympanic plate — is shaped in Neanderthal man as in the 
gorilla. In the modern type of man it has come to form 
the posterior slanting boundary for the glenoid cavity or 
mandibular socket (fig. 47, II.). 
In the auricular region of the skulls of Neanderthal 
men there is another simian feature to which attention 
may be directed, although it is not concerned in the 
function of mastication. In skulls of the modern type a 
pyramidal-shaped process of bone — the mastoid process — 
descends immediately behind the ear. To this process 
certain muscles of the neck, concerned in moving the 
head, are attached (see fig. 53). It is only slightly 
developed at birth, attaining its full size when the indi- 
vidual has reached adult years. In the gorilla a mastoid 
process is present, but in place of growing downwards to 
form a pyramidal process, it expands into a flange-like 
plate, forming part of the bony occipital platform on which 
the muscles of the neck are implanted (see fig. 47, II.). 
The pit or fossa from which the digastric muscle arises 
is left exposed on the anthropoid skull below the mastoid 
process. In skulls of the modern type the pyramidal 
process covers and hides the digastric fossa (fig. 47). In 
Neanderthal skulls the mastoid process does not assume 
a distinct pyramidal form ; in its shape and relationship 
