CARNIVORA. 



613 



M 



vegetable feeders. The dentition though essentially similar 

 throughout the group shows some variation which is generally 

 correlated with the mode of nutrition, though in the case of 

 the bears it would be difficult to distinguish the carnivorous 

 forms from the frugivorous by this character alone. 



The essential features are as follows : six incisors (very 

 rarely fewer) in each jaw, conical or chisel-shaped, set nearly 

 in a straight line across the jaw and usually increasing in size 

 from within outwards ; two powerful pointed canines pro- 

 jecting beyond the other teeth ; a variable number of grinders 

 divided as ^^ ^_^^ j /I r\ JT Jif 



usual into 

 premolars , 

 which have 

 predeces- 

 sors in the 

 milk denti- 

 tion, and 

 molars. 

 The lower 

 canines 

 bite in 

 front of 

 the upper, 

 which are 

 separated 

 from the 



incisors by a small gap. One of the grinding teeth on each side 



in each jaw is different from the rest and called the carnassial 



or sectorial tooth. In the upper jaw the tooth so modified 



is p 4, in the lower jaw w 1. The teeth in front of the 



carnassail are sharp and compressed, those behind it as a 



rule are broad and tuberculated. The former consist of a 



main cusp to which is frequently added a small anterior and 



posterior cusp. The carnassial tooth of the upper jaw {p 4) 



has when typically developed, an elongated trituberculate 



crown and three roots (Fig. 322, //). Two of these tubercles 



(2 3), of which the anterior (2) is the longer, may be said to 



constitute the outer blade of the tooth, while the third is 



low (4) and forms a talon-like process at the anterior end of 



Fig" 322.— Left upper carnassial teeth / of Felit, II of Canis.fll of 

 Vrsus, seen from the outer side and from below (from 1' lower 

 and Lydekker). 1 anterior, 2 middle, 3 posterior cusp of the 

 blade, 4 inner cusp of the upper carnassial, supported on distinct 

 root, 5 inner cusp posteror in position and without distinct root, 

 characteristic of the Ursidae. 



