ELEPHAS PRIMIGENIUS.— TRUE MOLARS. 109 



By compounding the foregoing and other data it seems to me that the ridge-formula 

 of the second true molar of the Mammoth exhibits a formula ranging from ce 14< x to 

 xlQ X (rarely), and in the lower jaw from cT 14 a? to x 18 ^. Moreover, that the most 

 usual formula in upper molars would seem to be ^ 15 ,r, and in lower x 16 — 17 x. The 

 ratios in the latter being, out of twelve entire molars, as follows :— Two had a formula of 

 X 14 X, two of a? 15 X, three of x 16 x, two of a? 17 ^, and two of x 18 x. 



The range in equivalent teeth of E. Asiaticus is not, as far as I have been able to 

 make out from many specimens, so great as in the Mammoth, and although as low a 

 figure as fifteen plates, and even seventeen plates, with talons, may occur occasionally, the 

 normal and very steady number of sixteen, besides accessory ridges, seems to prevail in 

 that species. 



The E. Hysudricus, whose dental characters present several interesting comparisons 

 with both of the preceding, shows in the approximation of its ridge-formula, as well as 

 the disk patterns, certain affinities with them, but more especially with the Asiatic 

 Elephant/ 



In comparing the tooth of E. antiquus with that of the Mammoth, I have stated 

 elsewhere^ that the ridge-formula of the latter seldom averages less than x\'o x, being 

 then unaware of the instances I have just pointed out, and resting on the data furnished 

 by Falconer. I believe this number is not nearly so frequent, at all events in teeth from 

 British strata, as the formulae x 14 x and x\'h x, which seem to me about equally common 

 to the second true molar in either jaw. Moreover, it appears to me extremely unlikely 

 that any practised observer would confound entire specimens of the Mammoth's second 

 true molar with that of any of its congeners. Fragmentary specimens will always be 

 puzzling, but a well-worn crown, with its high ridge-formula and characteristic sculpturing 

 of the worn surface, can scarcely be mistaken for that of any species hitherto described. 



T/te Ultimate or Third True Molar. 



The ridge-formula of the last of the dental series in the Mammoth ranges from x\'i x 

 to X 27 X, and probably individuals may be met with presenting a still higher number of 

 plates. 



The characters of the last tooth are too patent to lead to mistakes in practised hands, 

 admitting, as in all cases of other members of the series, it is perfectly entire and the 

 crown sculpturing pronounced. 



Upper Molars. — The lowest expression of ridges which has come under my notice is 

 shown in No. 47,122, B. M., in a tooth from " river gravel at Kettering, Northampton." 

 This upper molar holds ^ 18 ^ in 10x4^ inches, and eight ridges are contained in 4f 

 inches. The plates are thin and there is faint crimping of the machserides. 



^ Compare pi. vii, fig. 3, ' F. A. Sival.,' with fig. 4 of the same plate, erroneously stated as being 

 the tooth oi E. IIysu<h-icus, whereas it belongs to E. Asiaticus, ' Pal. Mem.,' i, p. 428. 

 2 ' Monograph,' p. 30. 



15 



