288 APPENDICES. 



II. Differences between the European and the American 

 Beavers. 



If naturalists have found it difficult to agree as to the proper 

 classification of the beaver, they have been scarcely less troubled 

 to decide whether the beavers of the Old and the New World con- 

 stitute one or more species. Some reference to this subject might 

 be expected in a work like the present; and in order to limit the 

 discussion I propose to examine only the views given by Dr. 

 Brandt, as being the latest and most elaborate, and probably the 

 most conclusive, that can be adduced in favor of the diversity of 

 species. 



In a series of essays published in the " Memoires de I'Academie 

 de St. Petersbourg," Brandt has discussed many questions relating 

 to the beaver with great ability and thoroughness of investiga- 

 tion. His conclusions on the point before us are expressed in 

 the following summar}^ : 



"1. From the investigations of Kuhl, Oken, and previously of 

 Brandt and Ratzeburg, no outward characteristic appears afford- 

 ing evidence of a specific difference. 



"2. That in respect to the relative size of the body, the Ameri- 

 can beaver, from previous experiences, does not differ from the 

 European in any essential particular, and probably not at all. 



"3. That in respect to the relation of the head-, ear-, foot-, and 

 tail-formation, no distinctive characteristics have yet been dis- 

 covered. 



"4. That, on the other hand, by the comparison of eight skulls 

 of the European beaver, with five skulls of beavers from the 

 northwest coast of America, manifold constant differences, in 

 part very striking, become apparent between the beavers of the 

 Old and New World. 



" 5. That many of the differences in these skulls involve also 

 variations in the external structure. 



" 6. That, finally, the well-known histological variation in the 

 castor sacs, which exists between the beavers of the Old and the 

 New World, and also the difference in the appearance of their 

 secretion, seem to establish a specific difference between the two.'" 

 P. 62. 



Excluding then, as we may do, all but the two points named, 



