FAUNA AMERICANA. 131 



most inaccessible and unexplored forests, which 

 is at least ver}^ uncertain. It is more than probable 

 that many species have disappeared and are en- 

 tirely lost since the present state of the surface of 

 our globe. 



Suppose an animal to inhabit the shores of the 

 great rivers of America previous to the discovery 

 of this continent, and not to be endowed with the 

 instinct of emigration, to become surrounded by 

 the habitations of civilized man ; hemmed in, and 

 cut off from all resources by the march of civili- 

 zation, the natural consequences would be de- 

 struction. 



It may be necessary further to remark, that all 

 the fossil beavers hitherto discovered, resemble 

 the recent species. 



Genus. 



Fiber, Cuv. Geoff. Illig. 

 Ondatra, Lacep. Geoff. 

 Castor, Briss. Linn. Erxleb. Bodd. 

 Mus, Gmel. 



CHARACTERS. 



{r Incisor 2. 

 superior 8. < Canine 0. 

 C Molar 6. 

 C Incisor 2. 

 inferior 8. s Canine 0. 

 C. Molar 6. 



Superior incisors plane and chissel form ; infe- 

 rior sharp, and rounded anteriorly ; molars com- 

 pound, presenting transverse zigzag plates. 



