FELINES. 493 



terior obtuse tubercle and a posterior larger compressed pointed 

 portion : the second lobe resembles that in Felis ; the third is re- 

 latively larger, equalling in some species, as Machairodus neogceus, 

 half the antero-posterior extent of the crown ; its trenchant edge 

 being, however, as in the Cats, horizontally sinuous. The upper 

 sectorial differs still more from that of the typical FelidcB in being 

 supported by only two fangs. The tubercular tooth is small, with 

 a more rounded crown than in Felis. The canines of the lower jaw 

 are much shorter than those above, and form the outer teeth of the 

 same transverse series with the incisors, like the lower canines of the 

 Ruminants, whose true nature they serve to indicate. The fore-part 

 of the lower jaw, which supports those teeth and the incisors is of 

 unusual depth, for the purpose of affording a kind of defensive but- 

 tress to the long sabre-shaped crowns of the upper canines, when 

 the mouth is closed. In this state the crown of the first lower pre- 

 molar (ib. p 3) is applied to the fore-part of that above, and is there- 

 fore strictly its analogue, answering, like the first lower premolar in 

 the true Felines, to the third premolar in the Dog. In Machai- 

 rodus neogoeus it is minute and simple ; in the small Machai- 

 rodus {M. megantereon)^ found fossil in France, it has a middle 

 compressed principal cone, with one basal tubercle in front, and two 

 behind. The second lower premolar (ib. p 4) is double the size, and 

 its true relationship to the last premolar of the upper jaw is here mani- 

 fested, not only by relative position, and mode of succession, but by 

 the form of the crown : the anterior basal tubercle is developed into a 

 sub-compressed cone, answering to the anterior lobe of the blade of 

 the upper sectorial ; the middle and largest compressed cone below 

 repeats the form of the middle lobe of the sectorial blade above, 

 whilst the sinuous edge of the posterior lobe of the upper sec- 

 torial is represented by the two better defined posterior basal 

 cones of the lower last premolar tooth. The third tooth of the 

 lower jaw of Machairodus (ib. m 1) which is a true molar, retains the 

 peculiar sectorial modification of the crown, which characterises it 

 in the normal Feline animals ; but its trenchant and sharp-pointed 

 lobes are more inclined backwards. The entire dentition of this 

 most extraordinary and formidable of extinct predaceous animals 



