MASTODON LONGIROSTRIS. 129 



whole of thein four. The ultimate tooth — ■ the seventh or last molar — has Mastodon 



Angusti- 



either four or five ridges. dens. 



Dr. Falconer is of opinion, that the distinction between the Mastodon 

 Angustidens and Longirostris has been overlooked ; that, in the former, no 

 proof exists that the penultimate molar has more than three ridges ; but in 

 the Longirostris or Arvernensis, the penultimate and the two preceding 

 molars have four ridges. On this ground, the Angustidens and Giganteus 

 are, in his opinion, more nearly allied than the Angustidens and Arvernensis. 

 He therefore would include in one section, which he calls Trilophodon, the 

 Mastodon Andium, M. Angustidens, M. Giganteus, and perhaps, M. Tapi- 

 roides ; and in another, Mastodon Longirostris or Arvernensis, M. Sivalensis, 

 and M. Latidens vel Cliftii. On the supposition that Dr. Falconer is correct, 

 we must change our views with regard to the relation of the Angustidens 

 to the Giganteus, and say that, instead of differing in nearly all the teeth, 

 it differs in the second milk molar, which has two ridges in the Giganteus, 

 and three in the Angustidens, and in the vertical premolar, which is not 

 found in the Giganteus. 



Passing over other differences which are not settled, it appears from 

 the above account, that, besides some variation in the forms and size of a 

 few bones of the skeleton, peculiarities exist in the form of the second tooth, 

 in the existence of an additional tooth, and in the comparative width of the 

 teeth generally. 



MASTODON LONGIROSTRIS. 



This, according to some authors, is not to be distinguished from the Mastodon 

 Mastodon Angustidens ; but, upon the authority of Professor Kaup, who tr l 

 has particularly investigated this subject, the Longirostris is distinguished, 



17 



