622 



UNGULATES. 



Cuvier has given a very interesting figure of a last molar in 

 this stage, (loc. cit. PL in, fig. 5) which has its grinding surface 

 reduced to an uniform disc of smooth dentine. 



The first molar (1) of the lower jaw of the Mast, angustidens, 

 was as small and apparently more simple in the crown, than that 

 ahove. M. M. Croizet and Jobert consider that it had but one pair 

 of cusps ; Dr. Kaup states that it is succeeded by a ' dent de remplace- 

 ment,' a figure of which he cites from Meyer's * Fossiles de Georgens- 

 mund,'Pl. l,fig. 2. 



The second molar of Kaup, which, if the first be so succeeded 

 vertically, should be the third, has three pairs of cusps, and an 

 anterior talon. The first pair of cusps or 'tubercles, are so much 

 smaller than the second, as to appear like a large bi-tuberculate 

 talon : the second pair is the largest, and forms the broadest part 

 of the grinding surface ; in the middle of the valley between this and 

 the third pair, there is ordinarily a small tubercle, which Dr. Kaup 

 found to be, in one instance, eaten away by caries. The posterior 

 talon is sometimes tuberculate, sometimes flat. Dr. Kaup indicates 

 the resemblance between these teeth, and that of the Mastodon 

 augustidens, from Simorre, figured by Cuvier, loc. cit. PL i, fig. 4. 



The lower molar, corresponding to the last of the deciduous series 

 {d 3) in the upper jaw, has three pairs of cusps and a posterior, 

 often large, talon ; the anterior pair is rather larger than the second ; 

 the posterior has a slight increase of breadth. Dr. Kaup figures one 

 of these teeth in which each pair of cusps has been worn down 

 to a single transversely oval cavity surrounded by enamel. 



The ante-penultimate lower molar has four pairs of cusps and 

 a posterior talon which consists of a small and single tubercle. The 

 anterior pair of cusps is complicated, with some small tubercles, 

 which are soon worn down. In a fully developed tooth, figured by 

 Dr. Kaup, PL xix, fig. 5, the two anterior pairs of cusps are abraded 

 to a single quadrilobate surface, and this is followed by five sub- 

 circular depressions, formed by the abraded summits of the two 

 posterior pairs of cusps, and the talon. The anterior pair of cusps 

 and part of the second pair are supported by a vertical and slender 



(1) Meyer, * Fossiles de Georgensmund,' PI. i, fig. 3. 



