CHAPTER XIV. 



TEETH AND THEIR VARIATIONS. 



To most persons the chief interest in connection with 

 teeth is an unpleasant one, owing to the circumstance 

 that through an artificial mode of life these highly im- 

 portant organs are subject to a premature decay, and 

 thus fail to perform satisfactorily their proper function. 

 With less civilised and savage races this, however, is 

 not the case, and among such people the teeth, almost 

 without exception, last in a sound and useful condition 

 throughout life; being gradually worn down to their 

 very roots with advancing age, and thus showing a 

 natural connection between the capacity of the teeth 

 to withstand wear and the normal span of human 

 existence. 



Regarded, however, from an anatomical, or, in modern 

 phraseology, a morphological point of view, teeth arc 

 among the most interesting parts of the animal organi- 

 sation with which the naturalist has to deal, owing to 

 the great and characteristic variations they display in 

 the different groups of Vertebrate, or Back-boned 

 Animals, and to the frequency with which they are 

 preserved in a fossil condition when other parts of the 



skeleton have either perished or are only preserved in 



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