300 THE MAMMALIA. 



organisation, or whether a further reduction is to 

 be anticipated ? Man is certainly one of the so- 

 called * persistent species,' but he is not uncon- 

 ditionally stationary. He varies as regards 

 dentition. Imperfect as are our statistics on this 

 point, this much is certain, that the cases of dis- 

 appearance or loss of teeth most frequently concern 

 the so-called wisdom teeth and then the outer 

 incisors. We do not of course know how often the 

 question has applied to the actual and complete loss 

 of the teeth, or only to some interference with the 

 teeth cutting the gum, occasioned by a limitation 

 of the necessary space. However, it must be re- 

 membered that the shortening of the jaw stands in 

 direct correlation with the reduction of the den- 

 tition. A prediction of the Man of the Future is 

 given us by Cope : the lower races of men will 



2 1 

 retain the dentition of the present day, i -, c -, 



O Q 



p ~, m -, while the intellectually higher races 

 2 o 



will be distinguished by the dental formulas : 



. 1 123 



1 V C 1' P * m 3 



, . I 1 2 Z 

 and i ~, c j, p -, m ~. 



