276 COMPARATIVE ANATOMY OF THE TEETH. 



chimpanzee it has but four cusps; in the orang, the fifth 

 external and posterior tubercle is feebly indicated. The 

 deciduous molars of the human subject, as in the chim- 

 panzee and orang, have each three fangs in the upper and 

 two in the lower jaw." 



In the order of succession in the teeth of these quadru- 

 mana and man, there is some difference. It has already 

 been stated, in the description of human dentition, that 

 the first true molar and first incisor are the earliest to 

 appear in the permanent set; and between these two 

 points, Mr. Hunter remarks, the teeth progress more rap- 

 idly than those behind. 



But in the quadrumana this is not the case, and the 

 progress is slower ; for in these the second molar is found 

 to precede the bicuspid, and the last molar the canine. 

 And the cause of this difference is assigned to the difference 

 in the food. Monkeys, living on fruits and meats, require 

 the use of their grinders at an earlier period than either 

 the canine or incisors. In the baboons and mandrills , which 

 are a step lower than the monkey tribe, we find their denti- 

 tion most especially distinguished from the human, by the 

 canine teeth presenting the ferocity and strength of the 

 carnivorous animals. Those of the mandrill are described 

 as " weapons most formidable for their size and shape," the 

 upper canines especially, which pass behind the crowns of 

 the lower incisors, and on the outside of the first lower 

 bicuspid, which seems pressed back, as it were, by the ac- 

 tion of the upper canines. A considerable space divides 

 the upper canine from the incisors a shorter one separates 

 it from the bicuspid. The first bicuspid of the lower jaw 

 is distinguished by the base of its crown having an unusual 

 anterior prolongation, which is reduced to a cutting edge 

 by the friction of the upper canine. 



The class of lemurs are the lowest in the scale of the 

 quadrumana, and differ from these in their dentition, as 

 well as from the human race, by having thirty-six teeth 

 instead of thirty-two ; the difference being in the bicuspids, 

 of which these animals have six to each jaw,, three on 



