THE MASTODON. 29 



various names, the scientists who bestowed these names, 

 the epoch to which each belonged, and the locality where 

 found. It will be noticed that the names of discoverers, 

 or those prominent in describing the remains, have been 

 given to several. 



Dr. Falconer has divided the European mastodon into 

 two groups, having reference to their teeth, viz : Triloph- 

 odon (three-ridge tooth), and Tetralophodon (four-ridge 

 tooth). The noted varieties of the first are the Borsoni, 

 tapiroides, angustidens, and Pyrenaicus; to the second he 

 assigns seven species, the most noted are longirostris and 

 arvernensis. To this may be added the American varieties, 

 obscurus, mirificus, Shepardi, and proavus. Intermediate be- 

 tween the two groups is the M. Pentelici ; for, like the first, 

 its second molar tooth is marked by three ridges, and like 

 the second it has four ridges on its third milk-molar. 



It is doubtful if the minute division, above given, will 

 assist in the advancement of this study. This list, how- 

 ever, must be cut down. It has been positively decided 

 that the tetracaulodon is the male of the M. giganteus. This 

 at once strikes from the list the T. tapiroides, T. Osagii, T. 

 Kochii, T. Haysii, and T. Bucklandii. This list is still 

 further reduced, because the M. Jeffersonii, Godmanii, Col- 

 linsonii, and Chapmanii, have also been assigned to the M. 

 giganteus. 



It would be foreign to the object of this work to enter 

 into the minute details which characterize the different 

 species, or to determine which, of the remaining list, should 

 not be classed separately, for any pretension to decide the 

 actual number would be undertaking a task which the 

 ablest palaeontolologists have seen fit to leave in a state 

 of uncertainty. An attempt, however, will here be made 

 to briefly trace out the general characteristics of some 

 of these varieties. 



