1896.] GBOGHAPHICAIi HACES Or THE COMMON FIELD YOLE. 599 



cement-spaces, with four inner and three outer angles. It is 

 interesting that this variation should occur in a species in which 

 the presence of five cement-spaces in the second upper molar (as 

 distinguished from four in nearly all other Voles) is characteristic. 

 The specimen in which the variation occurs is now in my 

 collection (no. 75). It is a very large male, and was killed by 

 Mr. J. Lewis Bonhote, at Jerkin in Norway, on July 28, 1895. 



3. On the Existence in Europe of Two Geographical Races, 

 or Subspecies, of the Common Field Vole. By G. E. H. 

 Bakrett-Hamilton, F.Z.S. 



[Received May 18, 1896.] 



1 wish to call attention to the existence in Europe of two 

 distinct forms of the Common Pield Vole (Microtus agrfsiis, Linn.). 

 My own attention was first drawn to this fact on the receipt of 

 some Voles, which Mr. J. Lewis Bonhoto Avas good enough to collect 

 for me in Norway. These Voles, although differing externally, 

 especially in size, and in cranial characters from English specimens, 

 possess dental characters which are identical with those of the 

 Common Field Vole as found in England. 



The existence of these two forms appears to have been noticed 

 so long ago as 1841, in which year Jeuyns ' described as a new 

 species (thus confirming the opinion of William Thompson of 

 Belfast, to whom he wished to give the credit of the discovery) 

 under the name of Arvicola ncfjlectus, Thompson, some Voles 

 collected by Thompson in Perthshire and Inverness-shire. Writing 

 in 1841" and 1847 °De Selys-Longchatnps made the suggestion 

 that M. agrestis and M. neglectvs might be only local races of the 

 same species, but preferred to regard the two as distinct until 

 their characters could be further studied. lie stated that 

 M. agrestis was to be found in Sweden and Norway, from Scania 

 to 66 degrees of north latitude, but not in the high mountains ; 

 and that it was also reported from Denmark and Finland. M. 

 neglectxm, on the other hand, had a more southern distribution, 

 embracing England, Scotland, Belgium, France north of the 

 Seine and west of the Moselle, and possibly the Pyrenees, in 

 1856 Dehne reported it from Saxony ; but subsequent writers, 

 including Blasius*, Fatio", and Bell', have regarded it as a variety 

 of M. agrestis, although the latter recognized the difference 

 between the two forms, for however distinct the extreme forms of 



' Ann. of Nat. Hist. vol. vii. pp. 270-274 (1841). 



'■^ Bull. Acad. Sci. Bruxelles, Sept. 1841. In tliiB paper the differences 

 between M. agrestis and M. arvalis, formerly confused, appear to have been first 

 clearly pointed out. 



3 Revne Zoologique, Oct. 1847, pp. 305-312. 



* Siugetbiere Deutschlands, pp. 369 & 372 (1857). 



^ Lea Campagnols du Basein du himnn, p. 70 (1867). 



« British Quadrupeds, ed. 2, p. 326 (1874). 



