ANATOMICAL PECULIARITIES 
H5 
point it will be enough to refer the reader to the diagrams 
given in fig. 49, which represent sections made at the 
middle line or symphysis of the lower jaw. The first 
figure represents a vertical section of the chin region of a 
very young gorilla — under two years of age. The upper 
or alveolar border, on which the incisor teeth are 
implanted, projects well in front of the lower border. 
Strictly speaking, there is no chin — at least no eminence 
at the lower border. On the hinder aspect of the 
symphysis (indicated by an arrow in fig. 49) there is a 
pit — the "genial" pit. From the lower part of this pit 
arise the two chief muscles of the tongue — the right and 
YOUNS GORIULA 
3PV - NEW 
NEANDERTHAL CALEDONIAN. 
MODERN ENGLISH. 
Fig. 49. — Sections of the lower jaw at the middle line or symphysis of a young 
gorilla, a man of the Neanderthal type (Spy), of a native of New Caledonia, 
and of a modern Englishman. 
a, attachment of the genio-glossus muscle ; b, of the genio-hyoid muscle ; 
c, of the digastric muscle. The arrow points to the genial pit. 
left genio-glossal muscles (r/, fig. 49). Beneath these 
muscles is a linear impression for another pair of muscles, 
also concerned in the movements of the tongue, the 
genio-hyoid muscles {b). Below the linear impression 
and on the lower border or aspect of the chin region 
another pair of shallow impressions in the bone mark the 
attachment of the digastric muscles which can depress the 
jaw and help to open the mouth (f, fig. 49). The 
second section in fig. 49 represents the condition of parts 
in a Neanderthal mandible — one found at Spy. The 
upper or alveolar border is still the more anterior or 
projecting ; the lower border and the region of the chin 
recede. There is no chin eminence. On the hinder 
