MURID& 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 (A. 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 Moray shire, 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 A. gapperi 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. 1 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 (M. lemmus, Fig. 



1 Baird, Mamm. North America, pp. xliv. 558 (1857). 

 2 Pallas, Zoogr. Rosso- Asiat. vol. i. p. 173 (1811). 



