MURIDA 467 
Field-Vole is one of the commonest of our smaller mammals, and 
frequents fields, woods, and gardens in enormous numbers, often 
doing very considerable damage in the latter, owing to its fondness 
for garden produce of all kinds. It is spread over the whole of 
Great Britain from the Hebrides southwards. Abroad its range 
extends from Finland to North Italy and from France and Spain 
to Russia. The Bank-Vole (4. glareolus) resembles in size and 
general appearance the common Field-Vole, but may be dis- 
tinguished by its more or less rusty or rufous-coloured back, its 
larger ears, and the relatively longer tail, which attains to about 
half the length of the head and body. Its molar teeth present 
characters so different from those of all other Voles as to have 
caused it to be regarded as belonging to an entirely distinct genus, 
for which the name of Evotomys has been used. Their chief 
distinction lies in the fact that, unlike those of all other Voles, 
their pulp-cavities close up in adult life, and they form distinct 
roots, more’ resembling those of the ordinary Rats and Mice. 
The enamel-spaces of these teeth number respectively 5, 4, and 
5 above, and 7, 3, and 3 below. The habits of this species are 
in every way similar to those of the Field-Vole. Its range in 
Great Britain extends northwards to Morayshire, beyond which it 
has not yet been observed. It is also found all along the north 
temperate zone from France to China, and is replaced in North 
America by a closely allied animal known as A. gapperi. It is 
probable, however, that both 4. gappert and A. glareolus are only 
southern climatic offshoots of a still more northern species, the 
A. rutilus of Northern Europe, Siberia, and Arctic America. 
Fossil remains of Arvicola are common in European Pleistocene 
deposits, and they have also been obtained from the Upper 
Pliocene of the Norwich Crag. 
Synaptomys..—Represented by one North American species, 
having grooved upper incisors, skull and molars like those of 
Myodes, with the external characters of Arvicola. 
Myodes.2— Distinguished from Arvicola by the more clumsy 
build, convex obtuse head, extremely short and Rabbit-like tail, 
short ears, small feet, the soles of which are furred, elongated claws, 
and thick fur, as well as by the breadth and massiveness of the 
skull, in which the zygomatic arch has a laminar expansion and 
the palate a peculiar contour; while the root of the lower incisor 
does not extend behind the last molar, the upper incisors are 
bevelled, and not grooved, and the molars have a characteristic 
pattern, which cannot be well explained without a figure. 
The Lemmings, as the members of the genus are commonly 
called, are represented by the Norwegian Lemming (J/. lemmus, Fig. 
1 Baird, Mamm. North America, pp. xliv. 558 (1857). 
2 Pallas, Zoogr. Rosso-Asiat. vol. i. p. 173 (1811). 
