CHALICOTHEEIID^;. 161 



46296. The greater portion of the mandible, showing all the teeth ; 

 {Fig.) associated with the preceding specimen. 



Presented by R. 0. Cunningham, Esq., M.D., 1874. 



Genus ELASMOTHERIUM, Fischer 1 . 

 Dentition : — I. £, C. J, Pm. |, M. |. The skull is essentially rhi- 

 nocerotic, but the cheek-teeth are taller than those of Rhinoceros, 

 and thus approach those of the Equidce and the Toccodontia (see 

 J. P. Brandt, Mem. Ac. Imp. St. Petersbourg, ser. 7, vol. viii. art. 4, 

 1864). The narial septum is ossified, and the frontals carry a large 

 bony protuberance for the support of an immense horn. 



Elasmotherium sibiricum, Fischer 2 . 



Syn. Elasmotherium jisclieri, Desmarest 3 . 



Hob. Northern Europe. 



M. 1890. Cast of the cranium, wanting several of the cheek-teeth. 

 The original is from the Pleistocene of Nouvonsensk, 

 Samara, Bussia. Purchased. 



M. 1891. Cast of an upper cheek-tooth. The original is from the 

 Pleistocene of Nouvonsensk. Purchased, 



Family CHALICOTHEMID^]. 



The upper premolars are simpler than the true molars ; the latter 

 (fig. 21, p. 165) usually have four columns, of which the two 

 hindmost are frequently connected by an oblique transverse ridge, 

 and there may be a less complete anterior transverse ridge. The 

 crowns of all the cheek-teeth are very low, and the upper ones 

 when worn present Y-shaped dentine surfaces ; those of the lower 

 jaw are crescentoid, and inTB has no third lobe. In the American 

 forms there are four digits to the pes and three to the manus. The 

 number of the cutting-teeth presents variations analogous to those 

 obtaining in Rhinoceros. On these grounds, coupled with slight 

 differences in the form of the cheek-teeth, a large number of genera 

 have been founded 1 ; at least all the Old-World forms are, however, 

 included in the present work in the typo genus. 



1 Program. Moscou, 1808 ; see also Mem. Soc. Imp. Nat. Moscou, vol. ii. 

 p. 255 (1809). 



2 Loc. cit. 



3 Mammalogio, Supplement, p. 546 (1822). 



4 See Cope, Proc. Amer. Phil. Soc. vol. xis. p. 300 (1881). 

 PART III. M 



