MIOROTUS 



719 



no constant cliai-acter in the enamel pattern by which they may 

 be distinguished. In the specimens examined the terminal looji 

 of wi^ is invariably short and broad, not showing any tendency to 

 the elongation occasionally occurring in M. nivalis. 



Bemarhs. — Microtus lehrunii is represented by two geographic 

 races, one of which is remarkable, in the sub-genus Chionomys, for 

 its occurrence at a distance from mountains and in a region of 

 unusually high summer temperature. 



MiCKOTUS LEBRUNII LEBRUNII CrespOH. 



1844. A\rvicold] lebrimii Crespon, Paune M^ridionale, i, p. 77. 



1857. Arvicola nivalis b. Arvicola Iciicurus Blasius, Siiugethiere Dcutsch- 



lands, p. 359 (part). 

 1908. Microtus Icbninii lebnmii IMiller, Ann. and Mag. Nat. Hist., 8th ser., 



I, p. 101, January, 1908. 

 1910. Microtus {Chionomys) Icbruni TrouGSsart, Faunc Mamm. d'Europe, 



p. 184. 



Tyjje locality. — Neighbourhood of Nimes, Gard, France. 

 Altitude, 180 m. 



Geogra]}liical distrihution. — Known with certainty from the 

 type locality only, but probably extending through the Cevennes 

 and the mountains of Auvergne. 



Diagnosis. — ^Back clear, very pale smoke-grey, without evident 

 wash of wood-brown ; skull with auditory buUte small and 

 flattened. 



Colour. — Upper parts a \ery pale smoke-grey with a faint 

 bluish tinge, particularly on neck and between ears, the back 

 faintly " lined " with black, the sides and rump nearly clear ; 

 underparts bufiy white, not sharply defined, the slate-black under 

 colour appearing irregularly at surface and producing a bluish 

 tinge ; sides of muzzle dull white ; feet and tail white 

 throughout. 



Skull. — Auditory bullae decidedly reduced in size as compared 

 with those of M. nivalis, so that the lower edge of bulla scarcely 

 extends beyond line of cutting edge of molars. 



Measurements. — Three adult males from the type locality : 

 head and body, 117, 121 and 122; tail, 56, 55 and 66; hind 

 foot, 18-6, 19-6 and 18-8 ; ear, 13, 14-2 and 14. For cranial 

 measurements see Table, p. 721. 



Specimens examined. — Six, all from the neighbourhood of Nimes {B.M., 

 Mottaz and Nimes) ; no exact locality, 2. 



Remarls. — This animal presents the anomaly of a member of 

 the nivalis group completely adapted to life in the hot dry plains 

 of south-central France, a region where its presence can in no 

 way be explained as due to special local conditions. A mounted 

 specimen in the Paris JNIuseum collected in Auvergne (probably 

 near Clermont-Ferrand) by Lecoq, and presented in 1854, is 



