THE TEETH OF VERTEBRATES 61 



usually, and is modified from a single cone. It 

 is the most primitive type of tooth, being" nearest 

 to the cone shape as found in the fishes and rep- 

 tiles in all parts of the jaws. In the mammals it 

 still preserves the primitive form, though modi- 

 fied variously in different classes. The lower 

 mammals have no canines, but the Dolphin and 

 Cetacea have conical canine-like teeth in all posi- 

 tions like the Reptiles. In the Marsupials it be- 

 gins to assume specialized forms. It is absent in 

 the Proboscidce and Rodentia and in some of the 

 Ruminants. In some of the Herbivora it is of 

 incisor-like form, and is ranged with these teeth 

 for cutting purposes. It is excessively developed 

 in the Musk-deer, Boar, Walrus, and other ani- 

 mals, for battle or other secondary purposes. 

 But it is in the Carnivora that the canine attains 

 its greatest glory. In its monstrous development 

 in some fossil carnivores it extended far beyond 

 the lower jaw, and was of a saber-like form which 

 is recalled in lesser degree in the extinct Cave 

 Tiger and the Lion and Tiger of today. In the 

 FelidcB these teeth are long, curved, and piercing, 

 for tearing flesh and destroying life. In the 

 CanidcB they are reduced in size, and are round 

 and stout. In the Baboon they are still of large 

 size, though reduced in the Monkeys and Apes, 

 and are lowered to the level of the other teeth in 

 Man. In man the canines are reduced in form 



