WJ> 323 



the month of May, attaininc^ggicMlffiffi*"! eighteen 

 months, and living for nearly twenty years. They were 

 formerly common in the New England States, where the 

 remains of their dams can still be seen ; they are gradu- 

 ally becoming extinct. Allied to the beaver is the curious 

 Sewellel (Haplodon ritfus) of the mountains of Oregon and 

 Washington Territory. It is nocturnal, burrows in the 

 ground, and is about the size of a muskrat. 



VALUE. Twenty thousand beavers are taken yearly in Asia, and 

 two hundred thousand in America. The incisors are used by the In- 

 dians as chisels, knives, and ornaments. Beaver-leather is used, and 

 castoreum in the manufacture of perfumery. 



FIG. 349. The Myopotamus coypu, a valuable fur-bearing animal, at home 

 in either salt or fresh water in South America. 



Rats {Murida). In this family are the rats, mice, 

 and their allies that are very generally distributed over 



are made of mud, and two-storied, the upper being out of water, in 

 which the families live, while below are stored the provisions for the 

 winter. The doors or openings connect with the water. The dams and 

 home are repaired year after year, wood for the purpose being collected 

 in the autumn, and when frozen the work is extremely solid, 



