42 CLASS-BOOK OF ZOOLOGY. 



used in the manufacture of hats ; but the odor of the 

 musk renders its flesh unfit for food. 



§ 140. The Field-mouse (Arvicoia Xanthognathus) has 

 a tail nearly as long as the body, round, and covered by a 

 velvet-like tegument. It lives in meadows and grass- 

 fields in abundance, and at the first hay-harvest their 

 nests are found in great numbers on the surface of the 

 ground. These are made very similar to a small bird's 

 nest, and generally contain six or eight young ones. 



§ 141. The Marsh Campagnoi (Arvicoia Riparius) may 

 be observed, when the tide is high, sitting upon the fallen 

 reeds, where it has the appearance of a lump of mud. 



\ 142. The Norway Rat (Mus decumanus) is nine 

 inches long, of a light brown color, intermingled with ash, 

 with a round tail, bare, and covered with scales. This 

 rat is a native of Norway, but was accidentally brought 

 in the timber-ships to England, and then to America, 

 where it is now found in great numbers. It brings forth 

 from twelve to eighteen young at a litter, and is omnivo- 

 rous. As the Norway rat is one of the most destructive 

 animals, and of no use to man, it is necessary to destro) 

 it as much as it is in our power, by means of cats, weasels, 

 terriers, traps, and even of poison, but not arsenic, which 

 is dangerous, and at the same time injurious to other ani- 

 mals. 



\ 143. The Black Rat (Mus Rattus) is nearly of a black 

 color on the upper, and of an ash color on the lower part of 

 its body : it was formerly a native of Europe, but is now 

 found in all parts of the globe, where it has been carried 

 accidentally in vessels. The black rat is an omnivorous, 

 destructive animal ; eats seeds, flesh, carrion, and in time 

 of famine, devours its own species ; it is the greatest de- 

 stroyer of sugar plantations, plunders the orange-trees, is 

 seen in the holds of vessels, and in the deepest mines. 



\ 144. The Mouse (Mus musculus) is smaller than a 

 rat, has a long, scaly, bare tail, and the same constitution 

 and natural disposition as the rat. The mouse brings fortl 

 five or six young at a litter, at all seasons, and severa 

 times in the year, which, in less than fifteen days, ait 

 strong enough to procure food for themselves. 



