ELEPHANT. 625 



only a thin layer of that substance is continued upon the unworn 

 enamel, as in the true Mastodons. 



With reference to the molar teeth of the M. latidens, Mr. CUft 

 remarks that, in comparison with those of the M. giganteuSy the 

 ridges are more numerous, less distant, and the interstices less 

 deep : they are also more sub-divided, and the teeth begin to assume 

 the appearance of those of the Elephant : — " On advancing to 

 Mastodon elephantoides, we shall find all these features of similarity 

 more strongly developed : — the points and ridges are still more 

 numerous, and the structure, were it not for the absence of ' crusta 

 petrosa', becomes almost that of the tooth of the Elephant." 



The diflPerence, in regard to the coronal cement, or * crusta 

 petrosa,' between Mastodon and Elephas, is not absolute, but pro- 

 portional ; although the quantity in the more deeply cleft crowns 

 of the Elephants' molars is considerably greater, the cement there 

 fulfilling its office of binding together the plates of the crown, w^hose 

 interspaces it completely fills. 



Whether the more essential characters of the genus Mastodon, 

 viz : the premolars, are present in the M. elephantoides of Clift, 

 has not yet been determined. Dr. Falconer informs me that he has 

 satisfied himself of the absence of the tusks in the lower jaw of very 

 young individuals, which forms another striking feature of the transi- 

 tional character of this extinct species. The same distinguished 

 Palseontologist, in conjunction with his accomplished and scientific 

 coadjutor. Captain Cautley, has brought to light the remains of 

 extinct species of Proboscidians with more deeply cleft molars, 

 occupied by the abundant cement which characterises the structure 

 of the grinding teeth of the Elephantine genus. The difference in 

 the thickness and height of the divisions of the crown of these 

 teeth in the Elephas planifrons and Elephas Hysudricus, F. & C, 

 establishes two intermediate links between the Elephantoid Mas- 

 todon and the Indian Elephant, in which latter species, amongst 

 existing animals, the teeth present the greatest complexity of structure. 



229. Elephas. — The dentition of the sole surviving genus of 

 the great Proboscidian Family includes two long tusks (PI. 146, 

 fig. 1, ?■) one in each of the intermaxillary bones, and large and 



s s 



