ELEPHANT AND MASTODON. 37 



Mastodon and the existing Indian Elephant, there is a series of 

 intermediate forms, which establishes an almost unbroken passage 

 from the one into the other. 



Fig. 6 a, pi. 2, represents a vertical and longitudinal section of 

 the last upper molar of an Indian fossil species, which we have 

 named Elephas insignis in this work. It is selected as furnishing 

 the best illustration of the intermediate type of a proboscidean 

 molar tooth, from which those of the other species diverge in oppo- 

 site directions. It is in the most favourable state of age and use 

 for showing the characters, the four anterior ridges being affected 

 bv wear, and the six posterior ridges entire, while the fangs are 

 fullv developed, their mode of implantation in the jaw being dis- 

 tinctly shown. The tooth is convex from back to front, in the out- 

 line of the crown. The white mass in the centre represents the 

 body of ivory, which is projected upwards in ten angular lobes ter- 

 minating in a sharp edge. The height of these lobes does not 

 much exceed the width of their base, and closely applied over 

 them is seen a thick layer of enamel, reflected up and down in a 

 continuous zig-zag plate. The interspaces of the five posterior 

 ridges of enamel are completely filled up by a mass of cement, or 

 ' cortical,' much exceeding the enamel in thickness ; and in quantity 

 in nearly as great an amount of development as the ivory core of 

 the ridge. This tooth belongs to one of the forms which have 

 been included under the name of Mast. Elephantoides, by Mr. 

 Clift ; and which Professor Owen names ' Transitional Mastodons.' 

 It is important to observe the characters presented by the cement 

 in this case, as its supposed absence or presence in the molar teeth 

 was the principal charactpr upon which Cuvier rested his generic 

 distinction between Mastodon and Elephant. Professor Owen, in 

 his Odontography, states, in regard to the teeth of this species, 

 that, " the interspaces are not filled with cement, as in the true 

 elephant : only a thin layer of that substance is continued upon the 

 unworn enamel, as in the true Mastodons." 1 But this statement 

 must be received with some modification. Fig. 7, pi. 6, represents 

 a portion of the same section drawn to the natural size, and com- 



1 Odontography, p. 624. 



