20 PACHYDERMATA. 



vered by Mr. Adams in Siberia. 1 He repudiates the validity of 

 the grounds for separating Mastodon from Elephas, in terms of 

 such strong dissent as to have excited the indignation of the 

 French philosopher r " Cuvierus in tractatu suo de hac specie 

 (M. giganteus) quam injuste ab Elephantorum genere separavit 

 quamquam non solum dentes molares, in quibus male genericam 

 diversitam 3 quaesivit lamellosse sunt structurae, ut omnes reliqui 

 Elephantorum molares sunt, sed etiam totum animal characteribus 

 genericis Elephantorum respondeat ejusdem opinionis est." Cu- 

 vier's division, however, has been adopted by every subsequent 

 writer except M. de Blainville, who coincides with the view taken 

 by Tilesius. 



A still more important oversight was made by the founder of the 

 genus, in regard to the statement which he advanced of the entire 

 absence of ' crusta petrosa, 1 or ' cortical' from the molars of Mas- 

 todon. It is true that this substance is not present in an appre- 

 ciable quantity in M. Ohioticus ; and that it is also but very 

 sparingly developed in M. angustidens and M. longirostris ; but 

 in M. Andium, a typical form of the genus, this substance exists in 

 a layer of considerable thickness, which we have observed in 

 almost all the teeth of the species, contained in the museum of the 

 Jardin des Plantes, including the specimens brought by Dombey, 

 Humboldt, and Gay, from Chili and Peru, and also in the rich 

 series of specimens from Buenos Ayres, lately acquired by the British 

 Museum. The great weight of Cuvier's authority has given an 

 undue influence to his statement upon this point, which has 

 biassed the observations of some later writers directed to the sub- 

 ject. 



No other additions were made to the species of Mastodon from 

 the second edition of the ' Ossemens Fossiles' until 1826, when 

 an important discovery was made, of fossil bones, along the banks 

 of the Irawaddi River, in the Burmese Empire, by Mr. Crawfurd. 

 These remains have been figured and described in the Geological 

 Transactions, by Mr. Clift, who has made a valuable contribution 



1 Tilesius, Memoir, de l'Acad. Imperial des Sciences de St. Petersburg, torn. v. 

 p. 452. 2 Oss. Foss. torn. i. pp. 11 and 225. s Sic in orig. 



