266 MAMMALS. 



all thrmiijh it. In the iuformorliato vogions hotwoon tlio tropu's nud the Arctic circle Loth occur 

 indiscrimiuatolv. Ficld-inicc do not occur in South America, South Africa, or Australia. 



Tiio Fidd-iuice are distributed very unit'onidy wlu-rcver tliey occur, different species being 

 aUottcil to the ditlerent kinds of locality to which they are suited. Some species inhabiting the water, 

 others the dry lands, while others, again, frequent rocky elevated regions, or Alpine luoimtain 

 heights. The thick moss and swamps of sphagnum in the Arctic regions are said to swarm with 

 species botli of Field-mice and Lemming to an extraordinarj- degree, aud to be the stai-ting-poiut 

 of the annies of Lemmings which from time to time have overrun the northern regions in incon- 

 ceivable numbers. 



The southern boundary of the Field-mice is not well defined ; but that they extend at least as 

 far south as Eome is too \\-cll authenticated by the mischief which the Ar^icoi.a terrestris {Bonap.) 

 does to the gardens aud vineyards there, by gnawing the young shoots, and b}' burro^^•ing in and 

 destropug the embankments in the neighboiu-hood of Leghorn. So great is the injuiy done by it, 

 and by the foxes, in scratching up the groimd in gardens to get at it, that the price paid for its 

 destruction at Eome is one half more than for the Mole. At least three species are found in Italy, — 



A. TERKESTKIS, A. AMFHIBIIS, and A. AKVALIS. 



It is interesting to tind the migratorj- instincts showing themselves in the southern species as 

 well as in the northern, when occasion calls it forth. Prince Bonaparte* mentions that it appears to 

 change its liabitat according to the rains, leaving the low comitry when it is inimdated, and gradualh' 

 advancing as the waters subside. In the year 1837, four-fifths of the entire harvest in the proviiu^e 

 of Piombiua, in Italy, were devastated by the Field-mice, which had been driven to the high grounds 

 by heavy floods in the meadows. In a single province in Germany, in 1822, 1,570,000 Mice were 

 captured in fourteen days, as shown by official reports." In like manner, the injury done by them 

 to yoimg trees and shrubs in America has sometimes proved excessive.f 



The long-tailed Field-mouse is scattered over almost the whole of the temperate regions of 

 Europe, and does considerable mischief by its economical habits. It lays up an astonishing amount 

 ("vast magazines," according to Pennant J) of acorns, nuts, corn, and various seeds, or even roots, as 

 a store for winter, as Yirgil says : — 



" Saepe eiiguus mus 

 Sub terris posuitque domos atque horrea fecit." 



The house and granarv alluded to by Yirgil is formed luider ground, either in holes excavated 

 by itself, or more frequently in small natural excavations imder the trunks or roots of trees enlarged 

 by themselves, or in the deserted rims of the mole. § 



The Field-mice are divisible into two sections, Arvicola proper and Hypud-EVS, the former 

 distinguished by the molar teeth being without roots, the latter by their having two roots ; and by 

 the former having the ears more or less concealed, while in the latter thej' are distinct and well 

 developed. 



Dr. Biiird, who has studied them carefiilly, saj-s, in regard to the Old and New-TYorld species : 

 " As a whole, the skulls of American Arvicol-E differ from the European, as in only one species, 

 (AR\ncoLA AGKESTis, fi-om Sweden) have I found an accordance in every general respect with the 



* BoxAP ARTE, " Iconographin delta Fauna Ifaliea." J Pesxant, Thomas, "British Zoology," 1812, vol. 1. 



t B.UKD, '• General Report U. S. Pacif. Railroad Explo- p. 148. 

 ration," vol. viii. 510. § Bell, Thomas " History of British Quadrupeds," 



1837, p. 306. 



