76 VERTEBRATES I MAMMALS. 



The Meadow Mouse, A. riparia, Ord., of the Northern 

 and Middle States, is four and a half inches long to the 

 tail, which is about two inches, the feet large, the color 

 dark brown above, ashy-plumbeous below. 



The Gray Mouse, A. Breweri, Baird, of the Eastern 

 United States, is about four and a half inches long to 

 the tail, feet very broad and stout, fur coarse, and the 

 color grayish yellow-brown above, ashy-white beneath. 



The California Arvicola, A. calif ornica, Peale, is about 

 the size of A. riparia, the fur very long and soft, color lus- 

 trous light yellowish-brown above, grayish-white beneath. 



The Prairie Meadow Mouse, A. austera, Lee., of the 

 Mississippi valley, is about the size of A. riparia, pale 

 cinnamon-rufous, variegated with black, below brighter. 



The Upland Mouse, A. pinetorum, Lee., of the Atlantic 

 States and westward, is three and a half inches long to the 

 tail, dark chestnut-brown above, hoary plumbeous below. 



The Genus Myodes Lemmings comprises little 

 mouse-like animals, the largest hardly as large as a rat, 

 with a broad skull, large fore feet, long claws fitted for 

 digging, and very short tail. Lemmings inhabit the 

 northern regions of both continents, and are celebrated 

 for their occasional extensive migrations. Norway, Swe- 

 den, and Lapland are sometimes overrun with these ani- 

 mals. Coming, in countless numbers, no one knows 

 whence, and going no one knows whither, they sweep 

 onward in a straight line, swimming rivers and lakes, nor 

 turn aside for scarcely any obstacle ; and they destroy 

 everything edible in their course. 



The Genus Fiber comprises the Muskrat, F. zibetliicus, 

 Cuv., abundant throughout North America, and twelve 

 to fourteen inches long to the tail, which is ten to eleven 

 inches ; the body thick and clumsy, tail much compressed, 

 and in its natural position sickle-shaped, the convex por- 

 tion being above, and the hind feet partly webbed. The 



