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Show 1896.1 GEOGRAPHICAL RACES O E T H E C O M M O N EIELD VOLE. 599 cement-spaces, with four inner and three outer angles. It 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. 2. On the Existence in Europe of Two Geographical Races, or Subspecies, of the C o m m o n Field Vole. By G. E. H. BARRETT-HAMILTON, F.Z.S. [Received May 18, 1896.] I wish to call attention to the existence in Europe of two distinct forms of the Common Field Vole (Microtus agrestis, Linn.). My own attention was first drawn to this fact on the receipt of some Voles, which Mr. J. Lewis Bonhote was 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 Jenyns ' described as a new species (thus continuing the opinion of William Thompson of Belfast, to whom he wished to give the credit of the discovery) under the name of Arvicola neglectus, Thompson, some Voles collected by Thompson in Perthshire and Inverness-shire. Writing in 18412 and 18473 De Selys-Longchamps made the suggestion that M. agrestis and M. neglectus might be only local races of the same species, but preferred to regard the two as distinct until their characters could be further studied. He 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. neglectus, 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 Blasius4, Fatio5, and Bell6, 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 JSTat. Hist. vol. vii. pp. 270-274 (1841). 2 Bull. Acad. Sci. BruxelJes, Sept. 1841. In this paper the differences between M. agrestis and M. arvalis, formerly confused, appear to have been first clearly pointed out. 3 Revue Zoologique, Oct. 1847, pp. 305-312. 4 Saugethiere Deutschlands, pp. 369 & 372 (1857). 8 Les Campagnols du Bassin du Leman, p. 70 (1867). 6 British Quadrupeds, ed. 2, p. 326 (1874). |