E. (EUELEPHAS) PEIMIGENIUS. 163 



lections at Florence, Pisa, and Turin ; all of -which, at the first and 

 last places, I have most carefully examined, with a view to determine 

 the point (1859). Dimensions of the lower left third milk molar : — 



Extreme length, 5-2 in. Width in front, 19 in. Width, behind, 2'4 in. Height 

 of crown, 3'5 in.] 



Taking the numbers yielded by the examples above given, 

 it is seen that the ridge-formula of the milk molars in E. 

 primigenius is identical with that of the existing Indian 

 Elephant, and liable to the same variation as regards the 

 antepenultimate, upper and lower, as is met with in that 

 species, namely, the ridges varying from seven to eight. The 



formula may be expressed thus : — ■- — ^-—-r, exhibiting a 

 J * 4 + 8 + 12 b 



progression by successive increments of four. 



c. Upper True Molars. — The circumstances which render it 

 difficult to determine with precision the ridge-formula of the 

 true molars in the existing Asiatic form apply equally to 

 those of the Mammoth ; and, in consequence, the ciphers of 

 the antepenultimate and penultimate, being the two posterior 

 intermediate molars, have heretofore been but vaguely ascer- 

 tained. Cuvier had not advanced sufficiently far in the 

 investigation of the subject to attempt to determine them. 

 De Blainville attributes from fifteen to sixteen ridges to the 

 antepenultimate, and eighteen or nineteen to the penulti- 

 mate, in the upper jaw. Owen considers the antepenulti- 

 mate (fourth in succession) to have been subject to consider- 

 able variation in the number and proportion of the ridges, 

 which he estimates as ranging from twelve to sixteen, the 

 greater number being usually in the lower molar. Of the 

 penultimate he describes the ridges as ranging even from 

 sixteen to twenty-four. Upon the examination and com- 

 parison of a very large number of specimens, I have been led 

 to the conviction that, ordinarily, the antepenultimate upper 

 true molar repeats the duodenary cipher of the last milk 

 molar, and that the penultimate, as in the Indian Elephant, 

 advances by an increment of four ridges. 



First, in regard of the antepenultimate upper, or fourth in 

 the order of horizontal succession. A very fine illustration 

 of this tooth in situ is presented by a specimen in the Museum 

 of the College of Surgeons (No. 620, Cat. Eoss. Mam. p. 153), 

 comprising the palate with a molar on either side, and in 

 front of it the empty fang-pits of the last milk molar which 

 had been shed. The crown of the antepenultimate is worn 

 to the last ridge, but quite perfect, and presents the discs of 

 twelve principal ridges, with talons ; it is very broad in 

 relation to the length, and, when compared with the corre- 

 sponding tooth of the existing Indian Elephant, it looks short 



SI 2 



