INTRODUCTION. 



Teeth are firm substances attached to the parietes of the begin- 

 ning of the alimentary canal, adapted for seizing, lacerating, dividing 

 and triturating the food, and are the chief agents in the mechanical 

 part of the digestive function. 



As secondary uses, arising out of the relations of co-existence 

 with other organs and endowments, or from a special development 

 of the teeth themselves, may be cited their subserviency to 

 speech(l), as ornaments, as characterizing age and sex(2), as in- 

 flictors of wounds either in combat(3) or defence(4), as aids to 

 locomotion (5), means of anchorage (6), implements of transport and 

 for working of building materials (7). 



The dental system thus presents many and peculiar attractions 

 to the anatomist and naturalist, for independently of the variety, 

 beauty and even occasional singularity of the form and structure 

 of the teeth themselves, they are so intimately related to the 

 food and habits of the animal as to become important if not essential 

 aids to the classification of existing species. 



And, while the value of dental characters is enhanced by the 

 facility with which, from the position of the teeth, they may be 

 ascertained in living or recent animals, the durability of the teeth 

 renders them not less available to the Palaeontologist in the determi- 



(1) Man. (2) Orang, Narwhal. (3) Dog. (4) Elephant, Musk-deer, (5) Morse. 

 (6) Dinothere. (7) Beaver. 



a 



