ORDER OF RODENTIA. 
445 
Rat, the Barbary Rat, and the Alexandrian Rat ; in Asia, the 
Giant Rat, the Caraco Rat, and the Perchal Rat ; in Australia, the 
Hydromys or Aquatic Rat, which is about the size of the Brown 
Rat, and lives in the water ; in America, the Brazilian Rat, and 
the Muscary Rat, larger than the Brown Rat, which occasions 
immense havoc in the plantations in the West Indies. 
The Field-Mouse Genus . — In contradistinction to the preceding 
genus, which have, generally speaking, the tail bare, and as long 
as the body, this appendage in the Field-Mouse genus is much 
shorter and hairy. This is the only important characteristic 
distinguishing the two genera. 
Among this genus may be found some very interesting, but 
also very mischievous species. As they make their abode in the 
woods and fields, and, besides, breed with prodigious rapidity, 
they sometimes become a serious plague to agriculture, and farmers 
do their best to exterminate them. 
The Common or Small Field-Mouse (Fig. 182) is found all 
over Europe, except in Italy; it is also met with in Siberia. 
It is about the size of the Common Mouse, and makes its abode in 
some raised bank, where it hollows out irregular passages, all 
meeting in one chamber. In this hole, on a bed of dry grass, 
the female gives birth to from eight to twelve little ones three 
or four times a year. We may judge by this how rapidly 
they multiply, and the extent of destruction to agricultural pro- 
duce which results from them. Whole districts have been 
reduced to destitution by this scourge. In 1816 and 1817 the 
one department of La Yendee experienced a loss estimated at 
£120,000, caused entirely by these animals. They were ulti- 
mately got rid of by poison. 
The Economic Mouse differs but little from the species just 
named, except that it is larger. It is a native of Siberia, between 
Daouria and Kamtschatka. The name which is given it alludes to 
one of its characteristic habits — that of hoarding up, during the 
fine weather, provisions for the winter. The labours and foresight 
of this puny creature are a constant source of admiration to the 
lovers of nature. Its domicile is of a somewhat complicated 
character, consisting of a principal chamber twelve inches in 
diameter, and about four inches high, from whence spring numerous 
little tunnels tending in every direction, and communicating with 
