6o8 MURID^— EPIMYS 



suggestion noted above ; the westward range of this form extends 

 through Irkutsk between latitudes 53° and 59° N., to Jenisseisk and 

 Krasnojarsk, near the meridian of 90° E. The Asiatic range of typical 

 norvegicus, according to Kastchenko, extends northwards from the 

 shores of the Caspian Sea from about 47" to about 59° N. latitude, and 

 eastwards almost to Tobolsk, near the meridian of 70° E. In the 

 region between 70° and 90° E. longitude, and the whole width of 

 Asia north of 60° N. latitude, there is no wild representative of the 

 species — a fact in accord with the experiences of Pallas and Midden- 

 dorfif. This discontinuity of distribution may perhaps be regarded as 

 proof of the ancient standing of E. norvegicus in Asia. 



It is possible that E. norvegicus was known to the ancients because, 

 as suggested by Pennant and more recently by Blasius, the "Mures 

 Caspii" described by .^lian {Anim., 47) as "little less than Ichneumons, 

 making periodical visits in infinite multitudes to the countries bordering 

 the Caspian Sea and swimming boldly over the rivers holding by one 

 another's tails," may have been of this species ; these were referred to 

 by Gesner under the name Mus aquatilis. 



The species first appeared in Europe in the beginning of the 

 eighteenth century, and it came both by land and sea. Pallas records 

 that in 1727, which was a "mouse year" in the Caspian region, vast 

 hordes of these rats migrated westwards after an earthquake; they 

 swam across the Volga, the bed of the river being choked with them, 

 and entered the houses of Astrakan in such numbers that nothing 

 could be preserved from them. From Astrakan the species gradually 

 spread westwards across Russia to the Baltic ; according to Bujak 

 (quoted by Blasius) it did not reach East Prussia before 1750, but 

 Zimmermann speaks of it as common in Brunswick in 1780. 



The earliest records of its arrival in Western Europe by sea are 

 provided apparently by the memoranda (cited recently by Winge, 

 Danmarks Pattedyr, 1908, 87) written in 1755 by Amtmand Urne of 

 Bornholm, and now preserved in the Zoological Museum of Copen- 

 hagen. Urne states that he had heard that these rats arrived at Copen- 

 hagen with the Russian fleet, which visited that city in 1716; he records 

 that they landed about 1725 from stranded Russian ships at Svaneke 

 on Bornholm, and that by 1755 they had nearly extirpated the Black 

 Rats at Bornholm. 



According to R. Brown {Arctic Manual, 1875, 21), the species was 

 carried to Greenland by Danish ships as far back as the days of 

 Fabricius, i.e., prior to 1780. 



CoUett states that the earliest Norwegian record is contained in 

 Strom's MS. diary (1756-1780), now deposited in the University 

 Library of Christiania ; Strom says that these rats arrived at Sondmor 

 from one of the neighbouring islands in 1762 and 1763, that they were 



