208 BRITISH FOSSIL ELEPHANTS. 



The extremes of the ridge formula are x\\x and a? 14 a?. In one upper it is a? 13 a?, 

 the other being x 14 x. In three lower, perhaps four, it is x 13 x, one has x 14 x and 

 another x 11 x. Perhaps, as inferred by Falconer, 1 an additional ridge might be present ; 

 but the enormous dimensions attained by the larger specimens render it very improbable 

 that the formula ever exceeded x 15 x. The longest molar of which I am cognizant is 13 

 inches in length, and the shortest, with the same formula, x 13 «?, is 9'4 inches in length. 

 As to width I find it ranges from 3 to 4 inches. It is true that the colossal teeth of 

 E. antiquus (p. 173, PI. XX, figs. 1 and 2), are much longer, but their plates are 

 crowded together, and the lower molars taper very much posteriorly, which condition 

 seems to be rare in E. meridionalis. 



It is unnecessary to repeat the characters which distinguish the crown of the latter 

 from that of the other two extinct species. The only molar with which one is likely to 

 confound it is an unusually thick-plated crown of E. antiquus^ but the expansion of its 

 disc and the pronounced crimping (not, however, invariably present on every disc), 

 together with a ridge formula not under xlbx, will suffice to distinguish such a molar 

 from that in question. 2 These comparisons are well shown in PI. XXIV, figs. 1 and 2, 

 as compared with the last molars of E. antiquus (PI. V, fig. 1, PI. IV, fig. 1, PI. Ill, 

 fig. 1, PI. II, figs. 2 and 3, and PI. XX, figs. 1 and 2) on the one hand, and of E. primi- 

 genius on the other (PI. VIII, fig. 3, PI. IX, fig. 2, PI. XIII, figs. 1 and 1 a, and PI. 

 XIV, figs. 1, 2, and 3). 



According to the foregoing data the ridge formula of the molar series of E. 

 meridionalis will stand as follows : 



Milk-Molars. True Molars. 



t — 



I. II. III. IV. V. VI. 



x3 x — ? x6x — ? x8x — ? x 8 x — x9x x9x — #lla: x\3x — x\Ax 

 x3x — ? x6x — 1 x8x — ? x7x — x9x x9x — x\\x x\\x — x\\x 



These figures, with the exception of my error referred to in regard to the penultimate 

 milk-molar, are substantially the same as were differentiated by Palconer from his 

 researches, with additions consequent on discoveries made since his essays were written. 3 



As compared with E.planifrons, whose molars (of all the Sewalik species) come nearest 

 to the above in regard to the dental elements and number of plates, the ridge formula, 

 according to Falconer, is as follows : 4 



Milk-Molars. True Molars. 



Aw 



I. 



x3x 



II. 



x 6 x 

 x 6 x 



III. 



x 7 x 

 x 7 x 



1 Op. cit., 

 8 Page 46 

 8 Op. cit., 

 * Op. cit., 



IV. V. 



x 7 x x 8 x 



x3 x 



x 7 x x8 — x9x 

 vol. ii, p. 118. 



vol. ii, pp. 118 and 1/6. 

 vol. ii, p. 91. 



VI. 



x 10 ar 



x 10 x — x \\ x 



