﻿INTRODUCTION. xxxiii 



mammoth (E. primigenius). His classification is based upon that most important part of 

 the digestive series — the dentition. 



a. Stegodon. — The remarkable deposits in the Sivalik hills yield the first indication 

 of a passage from mastodon into elephas in the presence of three species — Elephas 

 {Stegodon) bombifrons, insignis, and ganesa. E. {Stegodon) Clifiii, Falc., found by Mr. 

 Crawford in Ava, constitutes the nearest approach to Mastodon in the limited number of 

 ridges (six) of which its intermediate 1 teeth are composed. E. bombifrons and E. insignis 

 present the next stage in departing from the mastodontic type in the presence of seven, 

 eight, or even nine ridges in their intermediate molars. The Stegodons are differentiated 

 from the mastodons by the number of ridges on the crown ; by the convex outline of each 

 unworn ridge, by the absence of the longitudinal line of division along the middle of the 

 crown ; by the valleys being filled with cement ; by " the pronounced arc of a circle 

 described by the molars as we trace them forwards in the jaw ;" and by the inner side of 

 the upper teeth and the outer side of the lower being the higher, besides many other less 

 obvious points. A longitudinal and vertical section of the stegodon tooth showing " a 

 series of chevron-shaped ridges, of which the height does not much exceed the base, 

 and assimilating closely to the true mastodons," differentiates this group from the 

 succeeding ones. 



This group is confined to tropical Asia, and is now extinct. 



B. The next stage in departing from the mastodons is shown by the species of the 

 group Loxodon, that comprises the extinct Elephas planifrons, Falc., of the Sivalik Hills ; 

 Elephas priscus, Pale, and E. meridionalis, Nesti, of Europe ; and the living Elephas 

 Africanus. Its essential character " is that the ridges while closely corresponding " with 

 the former group, "in regard of number, are considerably more elevated and compressed," 

 showing, in a longitudinal and vertical section a series of elongated wedge-shaped pro- 

 cesses of enamel, intermediate in thickness between Stegodon and Euelephas. 



c. The third and last group, the most aberrant from the mastodontic type, is the 

 group of the Euelephas, comprising the living Indian elephant (E. Indicus), and the 

 extinct E. antiquus, Falc, and mammoth (E. primigenius), Blum., and some other species. 

 It is characterised by the number and thinness of the ridges or lamellae forming the crown, 

 and the flattened ellipse afforded by their sections on its worn surface, by the small quill- 

 shaped digitations that they present in the unworn tooth, and by the thinness and the 

 minute folds on the enamel. 



1 t. e. The last milk molar and ante-penultimate and penultimate true molars. See Falc., ' Quarterly 

 Journ. Geological Society' (1857), No. 52, p. 315. 



