116 MAMMALIA. GLIHES. 



A. palustris, Harlan. Fur dark grayish brown above, lead-coloured 

 below ; ears slightly edged with hair ; tail short, slightly hairy. 

 Inhabits the shores of the Delaware. Faun. Amer. 136. 



A. Pennsylvania, Ord. Fur brownish fawn-coloured above, gray- 

 ish white beneath ; eyes very small ; ears short and round. 

 Pennsylvania. Wilson, Ornith. vi. t. 50, fig. 3. 



A. Floridanus, Harlan. Fur lead-colour, mixed with black on the 

 dorsal line, yellowish on the flanks ; ears large and membranous. 

 Body about eight inches long. Florida Faun. Amer. 142. 

 This is the type of the genus Neotoma of Messrs Say and Ord, which differs from 



the Arvicola: in the teeth being furnished with roots. 



Gen. 94. LEMMUS, Cuv. Geoff. Mus, Lin. 



Incisors f , canines -g, molars g = 16. Molars with a flat 

 crown and angular plates of enamel ; ears very short ; fore- 

 feet in some species with five, in others four toes, proper for 

 digging ; tail short and hairy. 



L. Norwegians, Desm. (Mus Lemmus, Lin.) The Lemming. Fur 

 of a red fawn-colour, variegated with black and brown ; five toes 

 on the fore-feet. Norway and Lapland Pall Glir. t. 12, A, B. 



The migratory habits of these animals are very remarkable. They inhabit the alpine 

 or mountainous parts of Lapland and Norway ; and at particular but uncertain 

 periods they descend into the plains in immense troops, devouring every thing in 

 their passage. Their migrations are continued in a direct line, and no obstacles in their 

 way have any effect in altering their route ; neither ravines, torrents, marshes, or lakes> 

 nor even fires, make them deviate from their line of march. If a rick of hay or corn 

 occurs in their passage they eat through it ; and insurmountable objects make them 

 only deviate till the obstacle is passed. The grass is destroyed to the very roots in 

 the line of their march, and the ground appears as if ploughed. The cause of these 

 periodical migrations is not known. They seldom happen more than once in ten years. 

 Want of food and excessive multiplication have been assigned as the probable 

 causes ; and it has been remarked that their migrations take place in the autumn of 

 such years as are followed by a severe winter. If the instinctive propensity arises 

 from the numbers being too great for the supply of food, the object is amply attained ; 

 for the greater part of these immense hosts is destroyed by various enemies, owls, 

 hawks, weasels, &c. and numbers perish in the waters which their blind instinct 

 impells them to cross. Few survive to return to their native mountains. 



L. zokor, Desm. (Mtts aspalax, Pall.) The Daurian Rat, Penn. 

 Body reddish gray ; tail short ; fore-feet pentadactylous ; the 

 three intermediate nails very long ; eyes very small. Inhabits 

 the Altaic Mountains Pall. Glir. t. 10. 



L. Talpinus, Desm. Fur gray brown above, whitish underneath ; 

 fore-feet pentadactyle, with pretty strong nails ; eyes small ; tail 

 very short. Inhabits Southern Russia. Pall. Glir. t. 11, A. 



L. Hudsonius, Desm. Fur cinereous, with a dusky stripe down 

 the middle; fore-feet with four toes and the rudiment of a thumb; 

 the two middle nails very large, and apparently divided. Inhabits 

 Labrador Pall Glir. t. 26. fig. A, B, C. 



L. torquatus, Desm. Fur ferruginous, with a black dorsal line and 

 a white collar ; fore-feet pentadactylous ; nail of the thumb short 

 and rounded. Inhabits Siberia Pall Glir. t. 11, B. 



