32 
MAMMALIAN GALLERY. 
[Case 29.] 
[Cases 
29 & 30.] 
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, v/inter specimens of the English species 
being decidedly greyer and less ruddy in tint than those killed in 
summer. 
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. 
The Myomorpha, or Rat section (Cases 29 and 30), contains 
about 60 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 MyoxidcR, or Dormice, 
beautiful soft-furred, bushy-tailed little animals, natives of Europe, 
North Asia, and Africa, of which one small species, Muscardinus 
avellanariuSy the common Dormouse, is a native of England. 
(2) The MuridcBj or Rats and Mice, of svhich may be mentioned the 
Gerbilles of India and Africa [Gerhillus)^ 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 AVater-Vole or Water-Rat [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 1870-1891 108,200 Beaver-skins per annum. 
