402 CARNIVORES. 



divided from the posterior less convex surface by two finely ser- 

 rated ridges, at the base of each of which there is a tubercle : 

 the fang is longer and more compressed in Machairodus neogaus 

 of S. America, than in M. latidens. The canine figured in PI. 127, 

 fig. 6, is one of a few specimens of similar form and size which 

 have been found in ossiferous caves in England, associated with 

 remains of a large Tiger and other extinct Mammals. The com- 

 pressed crown presents no trace of the longitudinal impressions 

 which characterise the canines of the true Felis but is provided 

 with a double cutting edge of serrated enamel ; the posterior con- 

 cave edge is continued to the base of the crown, the anterior 

 convex margin becomes thicker as it approaches the base, like 

 the back of a knife, and the strength of the crown is further 

 increased by the expansion of its sides. Thus in the Machairodus^ 

 as in the Megalosaurus, whose teeth the present canines most nearly 

 resemble, each movement of the jaw combined the power of the 

 knife and saw ; the points of the teeth in making the first in- 

 cision would act like a two-edged sabre, and their backward cur- 

 vature would give them better holdfast. The first premolar of the 

 upper jaw (ib. fig. 5, p 3) corresponds with the second in the genus 

 Felisj and with the third in Canis and Viverra. The crown is elliptic, 

 low, with a middle compressed cone trenchant before and behind, 

 having a small blunt tubercle at the fore part of its base, and 

 two tubercles behind, the first conical and pointed, the second 

 obtuse. The succeeding tooth (ib. j; 4) is the sectorial, and is larger 

 in proportion to the preceding premolar than in Felis : it is, also, 

 much more ' carnassial' to use the Cuvierian term, having no 

 other indication of the internal tubercle than a slight basal thick- 

 ening of the blunt ridge which descends along the inner side of 

 the middle lobe of the blade : it is more like the deciduous than 

 the permanent sectorial in the true Cats. The crown of the 

 tooth consists of the antero-posteriorly elongated strong and 

 trenchant blade : it is divided into three principal lobes ; but 

 the anterior and smallest differs from that in the permanent 

 sectorial of the true Cats in being sub-divided into an an- 



tions, 1842, PI. 37, fig. 5, 6, 7. agrees with that oi Machairodus, to which genus the extinct 

 carnivore belongs by the namber and structure of the molar teeth. 



