208 SOME NOTES ON THE EAELY HOMlNIDiE 
pair of somewhat prominent tubercles which give origin to 
the genio-hyoglossi muscles. (See Pig. 7.) 
In all the apes this spinous roughened surface is absent, 
and is replaced by a depression. In most of the primitive 
jaws this ape-like condition maintains, but in none is it so 
marked as in the Heidelberg jaw. 
The jaw itself is very massive, the excessive breadth of 
the ascending rami pointing to an abnormal size of the masseter 
Mental 
spine. 
Mental ridge for genio-hyoid muscles. 
Fig. 7. — Vertical Mesial Section 
oe Inferior Maxilla of Modern 
Man. The upper mental spines 
form a pair, showing bilateral 
symmetry. The lower are in the 
form of a small median ridge. 
(Modified from Quain's Anatomy , 
vol. ii. pt. i.) 
muscles, and this in its turn hints at an enormous develop- 
ment of the zygomatic arches. 
A word before leaving Homo Heidelbergensis. The earliest 
known remains have been discovered in two deposits : (a) the 
Trinil beds of Java, and ( b ) the Mauer sands of Heidelberg — 
deposits laid down at a period not far removed from the dawn 
of the Pleistocene. 
As pointed out by others, it is interesting to note that 
the lower form ( Homo Javanensis) occurs in that portion of 
the world where the most primitive races (Australian &c.), 
until lately, continued to thrive; while on the other hand 
the higher form ( Homo Heidelbergensis) wandered over Europe, 
