268 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



fig. 8 of pi. 12, cited above, displays three teeth in situ, viz. in the 

 posterior extremity the last milk molar, in front of it the penulti- 

 mate milk molar (6) nearly worn out, and emerging from below the 

 latter a small vertically succeeding premolar (c) is exhibited. The 

 penultimate premolar is represented of natural size (c) in fig. 9 of 

 the same plate. It is considerably smaller in all its dimensions than 

 the antepenultimate milk-molar, fig. 1 a, drawn to the same scale. 

 It is of a roundish form, and shows no distinct indications of ridge- 

 divisions. It was therefore, in all probability, of but small im- 

 portance functionally in the economy of the species. In like manner 

 figs. 10 and 10 a of the same plate furnish an illustration of the last 

 lower premolar in situ, in front of the first or antepenultimate true 

 molar. That the latter is one of the true molars is clearly proved 

 by its large dimensions and by the mature form of the jaw. Fig. 

 11 6 represents the last premolar (natural size) vertically divided 

 through the middle, the anterior portion being wanting. Although 

 partly emerged, it is still imbedded in the alveolus, and intact, while 

 the tooth behind it is well worn. It is of comparatively small size, 

 but presents distinct indications of two transverse ridges, terminating 

 in the thick digitatious characteristic of the species. 



Of the upper premolars only the penultimate has been discovered 

 in situ. A beautiful example is seen in the cranial fragment repre- 

 sented by figs. 4, 5, and 6 of pi. 6 of the same work, on the left 

 side of the palate, the tooth of the right side having dropped out. 

 Behind the premolar are the last milk-molar, well worn, and the 

 antepenultimate true molar in germ. The premolar, in plain view, 

 is of a very broad or round oval form. The crown is composed of a 

 number of tubercles irregularly huddled together, somewhat in a 

 botryoidal manner, and presenting no distinct indication of trans- 

 verse ridges. The surface of the crown has attained the level of 

 the first disk of wear of the tooth immediately behind ; it bears but 

 slight marks of abrasion, which however appear to indicate that it 

 was opposed to a corresponding tooth below. This penultimate pre- 

 molar is represented of the natural size by fig. 6 of pi. 6 of the work 

 above referred to. 



Dr. Kaup has given a very instructive illustration * of the beauti- 

 fully preserved young lower jaw of M. (^Triloplioclon) angustidens, 

 which I detected in the collection of M. Ziegler Ernst at Winter- 

 thurf. The two premolars are seen in situ in this specimen, the 

 penultimate emerged, the last imbedded in the jaw, below the last 

 milk-molar. The specimens cited above place it beyond question 

 that the Sewalik species, E. (Loxodon) planifrons, had the premolar 

 series as complete numerically as either Dinotlierium giganteum or 

 M. {^Trilopliodon) angustidens. I have abeady explained that palae- 

 ontologists have heretofore entertained an opinion adverse to this 

 being found to occur in any species of Elephant. 



The above remarks may appear to be beside the professed object 

 of the essay, but they are essential to the proper estimate of the cha- 



* Beitrage, Heft iii. 1857, p. 9, tab. i. figs. 1-3, 

 t Vide Part 1, p. 324. 



