42 THE AMERICAN" BEAVER. 



tive antiquity of the three genera Castor, Gastoroides, 

 and Trogontlierium, and the unique and distinctive 

 type of animal life which they represent, should de- 

 termine the question in favor of the independence of 

 the Castoridse as a family. 



Another question remains, namely: whether the 

 American and European beavers are the same or dif- 

 ferent species. Linngeus, who founded the genus Gas- 

 tor in 1735, made but one species — C. Fiber. The 

 earlier naturalists, from Linngeus to Buffon and Cu- 

 • vier, accepted, without investigation, the specific iden- 

 tity of the European and American species. 



According to Brandt (Memoires, etc., 44), Oken was 

 the first in time (1816) who thought upon the question 

 of a possible difference of species. In 1819, Frederick 

 Cuvier (Hist. Nat. des Mamifers, No. 16) gave a pretty 

 full description of the external characteristics of a 

 Canada beaver in the Garden of Plants, but without 

 discussing the question of its possible difference from 

 the European. Again in 1825 (lb., No. 51) he de- 

 scribed a beaver of the Rhone, compared its skull 

 with tha,t of an American beaver, and then, for the 

 first time, pointed out the differences in its skull which 

 have since been recognized as establishing distinct- 

 ness of species. He also named the American beaver 

 GojStoT Americanus, and the European Gastor Gallicus. 

 Between these two periods (1820), Kuhl described a 

 Canada beaver in the British Museum, and named 

 it Castor Canadensis: but his description failed to 

 show any grounds of specific difference.^ 



^ " Castor Canadensis." " Supra rufus, infra rufescente cinereus. 

 Extremitatuni pallide brunescentium piles adpressis, brevibus, 



