6io MURID^— EPIMYS 



New Statistical Account of the Parish of New lands, Peeblesshire, 

 1834, 137; the date of its arrival in Morayshire is given as about 18 14 

 by the Rev. G. Gordon. 



We have no certain information as to the date of its introduction 

 to Ireland, but this probably happened soon after the arrival of the 

 species in England. Rutty {Nat. Hist, of Dublin, i., 281) says, however, 

 that it " first began to infest these parts about the year 1722." 



The species first arrived in the United States of America, probably 

 from England, about the year 1775 ; according to Audubon it was still 

 unknown from the Pacific coast in 185 1, although its introduction must 

 have occurred there soon afterwards (Lantz, The Brown Rat in the 

 United States, 1909, 13). 



The success of this animal as a colonist seems largely dependent 

 upon temperature and climate ; but the abundance or scarcity of food, 

 the presence or absence of suitable shelter, and the nature of the 

 competition to be faced, are doubtless factors of equal importance in 

 governing the distribution of this, as well as of other species. It has 

 therefore met with varied fortune in the many lands it has invaded. 

 In India, where the rattus group is at home, the foothold of norvegicus 

 appears insecure ; its colonies do not spread far from the landing places, 

 and it seems wholly incapable of displacing the native rats.^ In warm 

 temperate countries, like Italy and Spain, it has acquired a good 

 footing, but is forced to share the land with the "wild-coloured" 

 sub-species of rattus. In temperate Europe its success has been 

 marked ; it has spread everywhere and has practically ousted rattus. 

 Similarly on its arrival in New Zealand it promptly extirpated " Mus 

 maorium" Hutton, i.e., the descendant of the rattus stock previously 

 introduced by Europeans. In Switzerland its progress has been slow ; 

 it appears to have entered from Germany across the Rhine and Lake 

 Constance, and by 1869 had become common in some of the central 

 Swiss cities, as Berne and Lucerne ; but although at that time known 

 from many towns and several cantons, it had nowhere 'risen to any 

 notable height in the mountains ; and Fatio doubted whether it was 

 established then at Geneva, where the rattus group still predominated. 

 In Sweden and Norway it has almost completely displaced rattus, 

 but its range shows limitations similar to those of its predecessor, 

 and it is scarce in the most northerly districts. In Norway its advance 

 is said, by CoUett, to be slow ; it seems unable to colonise the upper 

 parts of the main valleys, and is lacking from the floors of all the 

 tributary valleys ; it is still scarce or wanting in many of the coastal 

 districts and inhabited islands. In northern Norway it occurs only in 

 buildings or in certain market places, as at Tromso and Hammerfest, 



' Bonhote {Proc. Zool. Soc, 1910, 65) says, however, that norvegicus is gradually 

 increasing in East India and Egypt at the expense oi rattus and other rats. 



