LOCALS EXTING: VOLES 467 
LOCALES ESTING VOLES: 
Microtus arvalis (Pallas, Nov. Sp. Quadr. e. Gir. Ord., 78, 
1778) differs from JZ. agrestis in its smaller size; broader, 
shorter, more depressed, and less angular brain-case ; and in 7” 
having only two instead of three salient angles on the inner 
side. Miller recognises four sub-species in western and central 
Europe, viz., 17. avvalis arvats, Pallas, known from Germany, 
Belgium, France, Switzerland, Austria-Hungary and northern 
Italy, characterised by its small size (hind foot, 15 to 17 mm. ; 
condylo-basal length, 23 to 25 mm.) and normal skull; J/. a. 
meridianus (Miller, Anz. and Mag. Nat. Hiist., February 1908, 
197) from south-western France (Pyrenees), a slightly larger, 
more yellowish form (hind foot, 15.8 to 16.6 mm. ; condylo-basal 
length about 25 mm.); JZ. a. duplicatus (Rorig and Borner, 
Arb, aus d. Kars. Biol. Anstalt f. Land- u. Forstwirthschaft, 
v., Heft ii., 73, 1905), from the Baltic coast of north-eastern 
Germany, a large pallid form with robust skull and deep brain- 
case (hind foot, 17 to 18.6 mm.; condylo-basal length, 25 to 
25.5 mm.), and J. a. devis (Miller, Ann, and Mag. Nat. First., 
February 1908, 197) from Rumania, southern Hungary, and 
north-eastern Italy, resembling dwpfzcatus in its large size and 
pale coloration, but with the skull slender, the brain-case long, 
narrow, and smoothly rounded, and usually with relatively 
large auditory bulla. Other nearly related forms carry the 
range of the species far to the east through Siberia and 
central Asia. 
On several occasions fossils from various British deposits 
of late Pliocene and Pleistocene age have been determined as 
belonging to 7. avvalis (e.g., from fissures near Bath, Somerset, 
by Blackmore and Alston, Proc. Zool. Soc., 1874, 468); but in 
most cases such records imply, because of the fragmentary 
nature of the material on which they are based, nothing more 
than the presence of a ‘“‘vole” with an arvaloid, z.e. a normal 
dentition. Some rather well-preserved cranial fragments have 
been collected from the late Pleistocene of Ightham by Abbott, 
Corner, and others, and Hinton (Proc. Geol. Assoc., xxi., 495) 
finds that these are “apparently identical” with J/. a. arvalis. 
