608 MURIDAZ—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 go° 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 go’ 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- 
dorff. This discontinuity of distribution may perhaps be regarded as 
proof of the ancient standing of 2. morvegicus in Asia. 
It is possible that Z. xorvegicus was known to the ancients because, 
as suggested by Pennant and more recently by Blasius, the “ ures 
Caspii” described by AZlian (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 aguatzlzs. 
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, z.2., prior to 1780. 
Collett 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 
