ARVICOLA 



745 



Diagnosis. — Essentially as in Arvicola terrestris, but more 

 modified for fossorial life, some of the races having become 

 completely terrestrial ; palmar and plantar tubercles reduced, 

 occupying less than half surface of region in which they occur ; 

 skull distinctly fossorial in form, the incisors strongly protruding ; 

 interparietal tending to be narrow and ligulate in outline. 



Skull and teeth. — The skull does not differ essentially from 

 that of Arvicola terrestris, but its fossorial characters are more 

 accentuated, especially in the terrestrial forms. Teeth without 

 special peculiarities. 



Remarks. — It may eventually be shown that some form of 

 Arvicola scherman intergrades with A. terrestris, but so far as the 

 material examined is concerned the two animals, though nearly 

 related, are distinct. Three races are now known, one of them 

 partly acquatic in its habits, the two others strictly terrestrial. 



Arvicola scherman scherman Shaw. 



1779. ? 8[palax] minor Leske, Anfangsgrunde der Naturgesch., i, p. 168 



(Germany). 

 1801. Mus scherman Shaw, Gen. Zool., n, pt. i, p. 75 (Strassburg, 



Germany). 

 1801. M[ms] amph\ibius'\ albus Bechstein, Gemeinn. Naturgesch. Deutsch- 



lands, i, 2d ed., p. 985 (Thuringen, Germany). 

 1801. M[us]amph[ibius] canus Bechstein, Gemeinn. Naturgesch. Deutsch- 



lands, I, 2d ed., p. 985 (Thuringen, Germany). 

 1804. Mus terrestris Hermann, Observ. Zool., p. 59 (not of Linnaeus, 1758). 

 1804. [Mus] schermaus Hermann, Observ. Zool., p. 59. Alternative for 



terrestris ; proposed but rejected on the ground that the animal 



was the same as that of Linnaeus (Strassburg, Germany). 

 1822. Arvicola argentoratensis Desmarest, Mammalogie, pt. n, p. 281 



(Strassburg, Germany). 

 1829. Lemmus arvalis $ buffonii Fischer, Synops. Mamm., p. 293 (near 



Berlin, Germany?). Based on Brants's account (Het Geschlact 



der Muizen, p. 372) of two specimens in the Berlin Museum 



supposed to be identical with the dark variety of " Le Campagnol " 



described by Bufion, Hist. Nat. des Anim. vn, p. 372. 

 1839. Arvicola terrestris de Selys-Longchamps, Etudes de Micromamm., 



p. 97, pis. I and II, fig. 6. 

 1858. Arvicola amphibius, c. A\rvicold\ terrestris auct., Blasius, Sauge- 



thiere Deutschlands, p. 355 (part). 

 1910. Arvicola scherman scherman Miller, Proc. Biol. Soc. Washington, 



xxiii, p. 21, March 23, 1910. 

 1910. Arvicola scherman Trouessart, Faune Mamm. d'Burope, p. x. 



Type locality. — Strassburg, Germany. 



Geographical distribution. — Continental Europe from the 

 Baltic south into central France and southern Germany ; limits 

 of range imperfectly known. 



Diagnosis.— Sole wrinkled but not conspicuously granular; 

 palmar and plantar tubercles relatively smaller than in Arvicola 

 terrestris, though not so much reduced as in the strictly terrestrial 

 forms ; length of hind foot about 26 • 5 mm. ; condylobasal length 



