464 
THE ANTIQUITY OF MAN 
central, two lateral — represent the moving blade. In 
both human and anthropoid dentitions (fig. 171) the 
lower teeth come into contact with the same parts of the 
upper teeth. The tooth which most demands our 
attention is the upper lateral incisor. When an anthropoid 
bites, the crown of the upper lateral incisor passes into 
the interval between the lower lateral incisor and lower 
canine (fig. 171). It wears each of these teeth. In fig. 
171, A, the crown of the upper lateral incisor comes 
in contact with the flattened crown of the lower canine ; 
in fig. 171, B, it has descended in front of the pointed 
(A) AUSTRALIAN. 
(B) CHIMPANZEE. 
jriQ_ 171. — A. The form of contact between the lower and upper teeth of a 
native Tasmanian. B. The form of contact in a female chimpanzee. 
crown of the lower canine. The articulation of the lower 
lateral incisor is also worthy of note. In both man and 
anthropoid the crown of this tooth forms a double contact 
with both upper incisors. So far as concerns the apposi- 
tion of the incisor teeth, man and ape are alike. The 
difference relates to the canine teeth. The lower canine 
of the anthropoid ascends in front of and to the inner side 
of the upper canine, until the point of the crown reaches 
the interval between its two upper opponents — the lateral 
incisor and canine (fig. 171, B). The articulation of the 
upper canine is even more important. In a front view 
this tooth is partly hid by the lower canine. Hence its 
points of contact are best seen from the side (fig. 
