140 dr. falconer's arrangement. 



conical eminences — between its ridges; which papillae exist in the other 

 two species. Further, M. Andium is distinguished by the quantity of 

 cement which fills the depressions between the ridges, and partly buries 

 the papillae. 



In the Tetralophodon group, the M. Latidens, like the M. Giganteus in 

 the other group, is distinguished from its two congeners by the absence of 

 papillae. . The M. Arvernensis has papillae ; but the mammillae are vertical 

 compared with those of M. Sivalensis, which are so very oblique that they 

 almost cross each other, the mammillae on one side being actually received, 

 in some cases, between those of the opposite side. 



Thus we have pointed out, as well as we could, in a brief manner, the 

 distinctive characters of the Mastodon teeth, according to Dr. Falconer, 

 though too briefly to do justice to his descriptions ; and, if these distinctions 

 are not made sufficiently plain, the blame must be attributed to us, and not 

 to him. 

 Apprecia- We shall not venture to give any opinion on the ingenious and valuable 



labors of this able palaeontologist, as the greater number of the species of 

 which he treats are not found in this country. When his great work is 

 completed, the subject will be investigated by scientific men in Europe, who 

 have much greater advantages for determining these distinctions than we 

 can have in this country. I will make only one remark. I should be very 

 unwilling, without a fuller knowledge, to place M. Giganteus and M. Angus- 

 tidens in the same group. The teeth of the two speties are very different in 

 form, size, and perhaps even in number ; and there are many differences 

 in the skeleton. A fuller investigation of the distinctive characters of 

 M. Arvernensis and M. Angustidens may lead to different conclusions on 

 the last-named question, but cannot alter the comparative character of 



tion. 



