32 MAMMALIAN GALLERY. 



Siberia, would appear so different from each other as to be readily 

 taken for three separate species, were it not that all the inter- 

 mediate stages are known. The colours, moreover, change some- 

 what according to season, winter specimens of the English species 

 being decidedly greyer and less ruddy in tint than those killed in 

 summer. 



[Case 29.] The Beaver (Castor fiber) (Case 29) is distinguished by its flat 

 and scaly tail, webbed hind feet, and soft, thick fur. Its incisor 

 teeth are of remarkable strength and sharpness, and it is able with 

 them to gnaw through the trunks of large trees, which it requires 

 for the construction of dams, in a short space of time. This 

 interesting animal is rapidly becoming exterminated, owing to 

 the great demand for its fur *, so that whereas it formerly in- 

 habited the whole of Northern Europe, Asia, and America, it is 

 now only to be found in a few isolated localities in the most inac- 

 cessible parts of its proper range. Some naturalists regard the 

 American Beaver as distinct from the European, and name it 

 Castor canadensis. 

 [Cases The Myomorpha, or Rat section (Cases 29 and 30), contains 



29 & 30. J aDOU t go genera and 500 species, which are spread over the whole 

 world, and externally present but few striking differences between 

 the various forms. They possess generally large ears, long and 

 more or less scaly tails, and bright prominent eyes. The families 

 included in this section are : (1) The Myoxidce, or Dormice, 

 beautiful soft-furred, bushy-tailed little animals, natives of Europe, 

 North Asia, and Africa, of which one small species, Muscardinus 

 avellanarius, the common Dormouse, is a native of England. 

 (2) The Muridce, or Eats and Mice, of which may be mentioned the 

 Gerbilles of India and Africa (Gerbillus}, with elongated hind feet, 

 on which they jump like kangaroos ; the Rats and Mice of the Old 

 World (Mures) } and the Vesper-Mice (Sigmodontes) of America; the 

 Voles (Microtus, or, as they have been commonly called, Arvicola), 

 whose best-known members are the common English Field- Vole 

 (Arvicola agrestis), the Water- Vole or Water- R-at (Arvicola amphi- 

 bius), and its ally the North-American Musquash (Fiber zibethi- 

 cus), a beautiful albino example of which is exhibited in Case 30. 



* In the years 1864-1875 the Hudson's Bay Company sold on an average 

 150,000, and in the years 1876-1891 108,200 Beaver-skins per annum. 



