42 PACHYDERMATA. 



plates. The entire tooth, which is seen in figs. 12 and 12 a of 

 pi. 7j wz 5^z/ in the jaw, is more elongated, and includes a greater 

 number of divisions than is usual in the last inferior grinder of 

 E. Hysudricus. The same general character, in the disposition 

 and relative proportion of the ivory, enamel, and cement, are exhi- 

 bited as in the upper molar (fig. 3 a), bearing in mind that the 

 latter is a younger and consequently smaller tooth. The layer of 

 enamel, however, is thinner than in the upper molar, owing to the 

 unusually large number of developed plates. The ivory segments 

 are curved backwards near their base, and the apices of the pos- 

 terior plates lean towards the front of the tooth, a disposition 

 which is still more strongly exhibited in the lower teeth of the 

 existing Indian Elephant. The granulated dark shade, below the 

 undulated outline of the ivory, indicates a core of sandstone, 

 which occupies the place of the unossified part of the pulp 

 nucleus, and of the undeveloped fangs. Both specimens, 3 a 

 and 3 b, are implanted in portions of the jaws. 



The existing Asiatic Elephant, E. Indicus, furnishes the next 

 modification represented in this plate. Fig. 2 a, shows a section 

 of the penultimate upper of molar of this species. The gradual 

 attenuation of the plates, successively exhibited from E. insignis 

 to E. Hysudricus, is here carried to excess, eighteen of these 

 divisions being comprised within the space occupied by about nine 

 in the equivalent tooth of the African species. They are pro- 

 duced vertically in the same proportion, the height of the middle 

 plate being about three-fourths of the entire length of the tooth ; 

 they, in fact, represent parallel perpendicular lamella?, of nearly uni- 

 form thickness, from the base to the apex, interstratified with layers of 

 cement of nearly the same thickness. The layer of enamel is 

 attenuated into a thin transversely undulated brittle plate, the sur- 

 face of which is deeply wrinkled with stria?, for the firm cohesion 

 of the cement. The general character of the section is a pecti- 

 nated arrangement of the lobes like the teeth of a comb, which 

 contrasts strongly with the chevron-formed ridges of E. insignis, 

 and the cuneiform plates of E. planifrons. The mass of ivory 

 at the base of the tooth is much thinner than in the corresponding 



