THE SKELETON OF APES AND OF MAN 249 



of the " corner " teeth (one on each side above and below), 

 also called eye-teeth, dog-teeth, or " canines." In the 

 highest apes, as in all monkeys, the canine teeth are very 

 large, and even tusk-like in the males, projecting above the 

 horizonal line formed by the crowns of the other teeth. This 

 projecting of the canine teeth results in their not meeting 

 one another point to point when the jaws are closed, 

 but necessitates one, the lower, shutting in front of the 

 other, and a space is left in the row of teeth, both in the 

 upper and the lower jaw, for this interlocking of the great 

 canines. It is called a " diastema." Man stands in strong 

 contrast to the apes in this respect. His canines do not 

 project beyond the level of the neighbouring teeth, and 

 there is no " diastema " or gap in either the upper or 

 lower row of his teeth.^ There is no trace of such a 

 gap nor any excess of size of the canines in any living 

 race of men, and what is more remarkable, the jaws of 

 very ancient prehistoric men which have been found in 

 the Middle Pleistocene — the Neander or Moustierian 

 men as well as the more ancient jaw from Heidelberg 

 (see p. 286) — do not show any difference in this respect 

 from the most advanced European race. On the other 

 hand, it is one of the most remarkable features presented 

 by the recently discovered " Piltdown " lower jaw that 

 it had a larger canine tooth than that of any recent or 

 fossil man, and consequently a gap or " diastema " in the 

 row of teeth (see Chap. XXX). This difference between 

 men and apes is all the more marked since the grinders 

 or cheek teeth (called also molars) of man and the 

 higher apes agree very closely, each to each in order of 

 their position, in the pattern formed by the irregular 

 surface of the crown. There are some slight differences 



^ See Plates VII. and VIII., p. 166, in "Science from an Easy 

 Chair," Second Series, for careful drawings of the complete series of 

 teeth in both the upper and lower jaw of Man and of an Ape. 



