' FALCONER — MASTODOJf X^B ELEPHANT. ' 261 



phantine affinities of this tooth are indicated by the absence of a 

 longitudinal line of division along the crown, and by the great 

 number of points (about eleven in each) that enter into the compo- 

 sition of the ridges. This tooth shows six principal ridges and a 

 small " talon." The penultimate true molar (or third of the inter- 

 mediate series) is presented in situ on both sides of the superb j^alate- 

 specimen re^iresented by Clift in pi. 36 of the memoir above referred 

 to. It is proved to be the penultimate by its large dimensions, and 

 by the circumstance that part of another tooth of stUl larger size, 

 and inferred to be the last, is seen behind it in the jaw. The same 

 specimen is more carefully represented by figs. 3 and 3 a of pi. 30 of 

 the ' Fauna Antiqna Sivalensis.' The crown-ridges are all more 

 or less worn, and partly damaged by fracture ; but enough remains to 

 show that the tooth was composed of six ridges and a hind talon. 

 The last true molar of the lower jaw is represented by fig. 5 of pi. 30 

 of the ' Pauna Antiqua Sivalensis.' The crown consists of eight 

 ridges and a talon. The anterior large fang had been absorbed, but 

 the portion of the crown sustained by it remains. The six posterior 

 ridges have their fang-elements confluent into a continuous plate or 

 shell, thus maintaining the Elej)hantine affinity indicated by the crown- 

 characters. Taking the data furnished by these teeth, the cipher 6 

 is seen to prevail in the two last of the intermediate molars, indica- 

 ting a Hexalophodont type, or 6 -|- 6 + 8 for the ridge-formula of the 

 true molars. 



3. Elephas (Stegodon) insignis. — The only other form among 

 the Stegodons, which it is necessary to notice, is that for which 

 the name of E. {Steg.) insignis has been proposed. In this 

 species the crown-ridges are constructed very closely upon the 

 model of E. {Stegodon) Cliftii, the principal difference consisting 

 in the much greater mass of laminated cement that fills up 

 the valleys. In some sections, as many as eleven distinct strata 

 of this substance may be counted*. But the ciphers yielded 

 by the " ridge-formula," place the species in close affinity with the 

 Loxodons, and more particularly with the species named E. (Lox.) 

 planifrons. Remains of E. (Steg.) insignis have been discovered in 

 immense abundance in the Sewalik Hills, and specimens illustrative 

 of the dentition of every age and in every stage of wear are con- 

 tained in the great Indian collection of the British Museum. The 

 rigid constancy in the number of ridges observablein the two subgenera 

 of Mastodon is no longer maintained. As stated in the preceding 



ing part of this paper, the former name is retained for the specimens of the 

 Tetralophodon type, figm-ed by Mr. Clift, pi. 37. figs. 1 & 4; pi. 38. fig. 1, & 

 pi. 39. figs. 1, 2 & 3. Of the others, the palate-specimen, pi. 36 {Mastodon la- 

 tidens, Clift), together with the detached molar, pi. 38. fig. 6 {Mastodon Ele- 

 phantoides, Clift), are referred to E. {Stegodon) Cliftii; and the lower-jaw spe- 

 cimen, pi. 38. fig. 2 (also M. Elephantoides, Clift), is referred to E. {Stegodon) 

 insignis. The specimens regarded by him as of his M. Elephantoides being 

 here considered to belong more properly to the genus Elephas, it became ne- 

 cessary to resort to another specific designation. Hence the origin of E. ( Stegodon) 

 insignis. 



* Fauna Antiqua Sivalensis, pi. 6. fig, 7* 



