26 PACHYDERMATA. 



into four genera, Elephas, Mastodon, Tetracaulodon, and Dino- 

 therium, to each of which he attributes a different dental formula. 

 He admits thirteen species of Mastodon, and discriminates six 

 species of Tetracaulodon among the Mastodontoid animals of 

 North America. Mr. A. Nasmyth adopted similar views, from a 

 minute microscopical examination of the structure of the tusks in 

 these extinct animals j 1 but the importance of the differential marks 

 indicated by Dr. Grant and Mr. Nasmyth, has not been admitted 

 by subsequent observers, as characterizing more than individual 

 and sexual varieties in different animals of the same species. The 

 generally received opinion at present is, that M. Ohioticus is the 

 only Mastodontoid form hitherto met with in North America. 



In the additions to the last edition of the ' Ossemens Fossiles,' 

 Cuvier has recorded the discovery of fossil grinders of Mastodon, 

 in the Lignite beds of Kcepfnach and Ellg in Switzerland, which 

 he has referred to his * Mastodonte a dents etroites.' 2 Some of 

 these remains have been described by Schinz as indicating a 

 distinct species for which he has proposed the name of M. 

 Turicensis. 3 M. de Blainville refers them to M. Tapir oides, as 

 defined in the ' Osteographie.' 



Two species of Mastodon have been proposed by Eichwald, 

 from remains found in Poland, under the names of M. Podolicus i 

 and M. intermedins ; 5 the former of which appears to be founded 

 on a disguised fragment of the lower jaw of Dinotherium gigan- 

 teum, and the evidence adduced in support of the latter is in- 

 sufficient as yet to establish its specific independence. M. de 

 Blainville refers it to M. Tapiroides. 6 



One of the authors has described some of the remains of a 

 typical species of Mastodon, from the tertiary deposits of India, 



1 Nasmyth, he. cit. June 1842, p. 775, ' On the Minute Structure of the Tusks of 

 Extinct Mastodontoid Animals.' 2 Oss. Foss. 8vo. edit. 1834, torn. ii. p. 366. 



3 Schinz, quoted in von Meyer's « Palaeologica,' 1832, p. 72, and in Bronn's 

 'Jahrbuch' of 1839, p. 2; mentioned in Jameson's Edin. New Phil. Jour. vol. v. 

 1828, p. 273, as a communication to the Helvetic Society of Nat. Hist, in August 1837- 



* Vide supra, note, p. 4. 



5 Eichwald, ' Zoologia Special.' 1831, vol. iii. p. 361. 



e Osteographie, ' Des Elephants,' p. 259. 



