A NEW FOSSIL PACHYDERM. 261 



interrupted by the prolongation of the posterior internal pyramid. 

 There is no internal basal margin, except at the expansion of the 

 valley between the ridges. This valley is deeper at the extrem- 

 ities than in the middle, where it is penetrated by an anterior pro- 

 longation of the posterior internal pyramid. The anterior margin 

 of this tooth is oblique, the external angle being prominent, and 

 more rounded than the internal. This proves the existence of a 

 slight angle at the junction of the molar with the premolar series, 

 to accommodate the position of the teeth to the compressed form of 

 the head anterior to the molars. The line of insertion of the in- 

 ferior molars follows the same course, and will be found hereafter 

 to strengthen this deduction. 



The second molar is quite similar to the first, but is regularly 

 quadrate, the anterior margin not being oblique ; the figure and de- 

 scription already given will serve to identify it perfectly. It may 

 be stated that this tooth was found in juxtaposition with the third 

 molar ; the whole series of that side were imbedded in a thin mass 

 of very hard cement, but the roots having entirely decayed, the 

 specimens were so fragile, that, in endeavouring to expose the 

 crowns, the first molar was entirely destroyed ; for this reason, the 

 third and fourth premolars, and first molar, are figured from an older 

 and slightly larger specimen than the one which furnished the third 

 molar. 



The third molar, m. 3 (fig. 13'), also of the left side, is longer than 

 wide, slightly narrowed behind, emarginate on the sides, with the an- 

 terior external angle a little prominent, and more suddenly rounded ; 

 the sculpture is similar to that of the first and second molars, but 

 in addition, the posterior basal cingulum rises into a small uneven 

 cusp, connected with the internal pyramid of the posterior em- 

 inence : on the externo-posterior face of this pyramid a trapezoidal 

 plane is developed by"wearing, extending to the basal cusp. 



