VERTEBRATES I MAMMALS. 



American Beaver, C. canadensis, Kuhl. 



in the banks, 

 whither they 

 retire when 

 their houses 

 are attacked. 

 The general 

 color of the 

 beaver is a 

 uniform red- 

 dish-brown, 

 and the fur 

 is of the best 

 quality, and 

 was former- 

 ly very valuable. Only two species are known. 



The American Beaver, C. canadensis, Kuhl., found all 

 over North America ; and the European Beaver, C. fiber, 

 Linn., of the Old World. These are much alike. 



The Genus Castoroides comprises the Fossil Beaver, C. 

 Moensis, Foster, of New York and westward, known only 

 from its skull, which shows that this beaver-like Rodent 

 was six times the bulk of our living species, 



Our existing beavers attain the weight of about forty 

 pounds, and the Castoroides would therefore weigh at 

 least two hundred and forty pounds. Its skull is over 

 nine inches long, four inches high, and seven inches 

 wide. 



The Genus Aplodontia comprises the Sewellel, A. lepo- 

 rina, Rich., of Puget's Sound, which is about the size and 

 general appearance of the muskrat, but with the tail ver/ 

 short and much depressed. 



SACCOMYIDvE, OR POUCHED GOPHER FAMILY. Thi& 



Family comprises Rodents which have large and distinct 

 external cheek-poucnes, pelage composed of stiff hairs 

 with no under fur, molars ^, and the upper lip not cleft 



