ELEPHANT AND MASTODON. 



tidens is ,^3^3- in the deciduous series, and 3),^^^^ in the 



true molars.^ 



M, de Blainville has entered at great length, in his ' Osteo- 

 graphie,' on what had been previously written regarding 

 M. angustidens, and he has given a beautiful series of illus- 

 trations of all the teeth in succession, in both jaws, as he 

 conceives them to be developed in this species. The rich 

 collection of specimens, discovered by M. Lartet and others 

 in Gascony and along the flanks of the Pyrenees (a large 

 portion of which is displayed in the palseontological gallery 

 of the Paris Museum), furnishes ample materials for estab- 

 lishmg the sj)ecific indej)endence of M. angustidens and M. 

 longirostris. But M. de Blainville has not attached sufficient 

 importance to the constancy of the ridge formula ; he has 

 throughout his illustrations intercalated Eppelsheim teeth of 

 the latter species, having four ridges, with Gascon specimens 

 of the foi-mer, having three ridges. In consequence, the teeth 

 of the two species are not merely intermixed, but a wrong 

 position in the jaw is in many instances assigned to M. 

 Lartet's specimens of the true M. angustidens. This remark 

 applies, without exception, to the determinations of the two 

 last teeth of the upper jaw. Giving a numerical expression 

 to M, de Blainville's descriptions of the different teeth, the 



., „ , . -_ ,., ITT 2 + 3 + 43 + 4 + 6 



ridge lormula m M. angustidens would be 2 + 2 + 3 ' 3 + 4 + e' 

 respectively, in the three deciduous and three true molars 

 on each side of both jaws. It is apparent that the lower 

 numbers do not coincide with the upper, and that, followed 

 in sequence, they deviate widely from the uniform succession 

 of three ridges presented by the last deciduous, and the first 

 and second true molars, in If. Ohioticus. 



Professor Owen has on two occasions described in detail 

 the dentition of M. angustidens, and the result stated in his 

 ' Odontography' is, that he has seen as yet no evidence that 

 the teeth described by Cuvier and by Kaup characterize diffe- 

 rent species. In his ' British Fossil Mammalia ' he identifies 

 English sj)ecimens with some of the typical forms figured by 

 Cuvier, and the number of ridges which he assigns to the 

 different teeth, according to their succession, is 2 + 3 + 3 

 to the deciduous molars, 2 to the small premolar, and 3 + 4 -f 5 

 to the true molars.^ This formula is liable to the same ob- 

 jections as that put forward by M. de Blainville. In his 

 ' Odontography,' however, published subsequently. Professor 

 Owen describes the teeth of M. angustidens in a different 

 manner, and the number of ridges assigned by him to the 



' Lotlisea Geognost. p. 1239. 2 British Fos. Mam. p. 286. 



