498 



CARNIVORA 



throughout the suborder, they are greatly modified in different 

 genera. The upper carnassial is the most posterior of the teeth 

 which have predecessors, and is therefore reckoned as the last 

 premolar (p 4 of the typical dentition). It consists essentially of a 

 more or less compressed blade supported on two roots and an inner 

 tubercle supported by a distinct root (see Fig. 220). The blade 

 when fully developed has three cusps or lobes (1,2, and 3), but the 

 anterior is always small, and often absent. The middle lobe is 

 conical, high, and pointed ; the posterior lobe has a compressed 

 straight knife-like edge. The inner tubercle (4) varies very much 



hi 



JL 



M 



Pig. 220. — Left upper carnassial teeth of Carnivora. I, Felis ; II, Cants; III, Ursus. 

 1, Anterior, 2, middle (paraeone), and 3, posterior (metacone) cusp of blade ; 4, inner tubercle 

 (protocone) supported on distinct root ; 5, inner cusp posterior in position, and without 

 distinct root, characteristic of the Ursidcc. 



in extent, but is generally placed near the anterior end of the 

 blade, though sometimes it is median in position. In the Ursidce 

 alone both the inner tubercle and root are wanting, and there is 

 often a small internal and posterior cusp (5) without root. In this 

 aberrant family also the carnassial is relatively to the other teeth 

 much smaller than in the rest of the Carnivora. The lower 

 carnassial (see Fig. 221) is the most anterior of the teeth without 

 predecessors in the milk-series ; it is therefore reckoned the first 

 true molar (m 1). It has two roots supporting a crown, consisting 

 when fully developed of a compressed bilobed blade (1 and 2), a 

 heel, or talon (4), and an inner cusp (3). The lobes of the blade, 

 of which the hinder (2) is the larger, are separated by a notch, 

 generally prolonged into a linear fissure. In the most specialised 

 Carnivora, as the Fdidce (I), the blade alone is developed, both 

 talon and inner cusp being absent or rudimentary. In others, as 



