DISTINCTION INTO SPECIES. 123 



Tetracaulodon Tapiroides 

 „ Osagii 



„ Kochii 



„ Haysii 



„ Bucldandii 



Proposed by Professor Grant. 



Many of these distinctions are founded, not on the comparison of 

 skeletons, or of very considerable parts of skeletons, but on some slight 

 variety in the size or form of a tooth. 



The multiplication of species on doubtful grounds impedes the progress 

 of natural science, and ought, of course, to be avoided where the lines of 

 distinction are not strongly marked. For, in many instances, such divisions 

 may separate from each other those animals which have the closest resem- 

 blance except in a single point.* 



The number of species of Mastodons which the present state of science 

 has fully distinguished appears to us to be more limited than that enume- 

 rated. Of them, we shall notice, as distinct species, the Mastodon Gigan- 

 teus, M. Andium, M. Humboldtius, M. Angustidens, M. Longirostris, M. 

 Sivalensis, and M. Latidens ; leaving to more able hands to trace the 

 characteristics which may be found to designate a greater number. It 

 will be seen, therefore, that it is not my intention to determine the actual 

 number of species, but rather to mention those whose characters have 

 been satisfactorily distinguished, without making any pretension to settle 

 differences, which have been left in a state of uncertainty by the most 

 able scientific men of the age. 



* " It is true, indeed, that the most manifestly natural mammalian genera are those, the species of 

 •which are provided with absolutely similar molar teeth ; and that those genera which include species with 

 molars of different forms do not present the same character of unity. But it does not follow, that, by 

 combining species of mammals with similar molars, a group will be formed perfectly analogous to those 

 which may he considered as the most natural or perfect. Neither the molar teeth nor any other solitary 

 character will serve to establish a natural classification." — Owen's Odontography, p. 70, Introd. 



