VERTEBRATA. 293 



Thus the more numerous the teeth of the molar series^ 

 and the broader their crowns, the more likely is it 

 that the creature subsists on a mixed diet ; and a 

 gradation may be traced even in individual teeth, 

 such as the carnassials, in which a gradual increase in 

 relative size of the internal tubercular cusps of the 

 upper, and of the posterior tubercles of the lower 

 teeth, may be traced as we pass from the examination 

 of the teeth of the Felidm (cats) to those of mixed 

 feeders, such as the Arctoidea " (bears). 



Fig. 115.— Skull of Wild Boar, Su8 serofa fera, showing tusk-like canines. 

 (From-Claus and Sedgwick.) 



The Canine Tooth. — The canine tooth, popularly 

 supposed to be a characteristic of carnivorous dentition, 

 is such only in so far as it is the tooth that enables an 

 animal to seize its prey : it is the fighting tooth, and 

 may exist in animals that are purely herbivorous. It 

 was shown by Cuvier, and long previously by Aristotle, 

 that although the canine is absent in many nearly 

 related animals, yet it is present and very long in 



