864 



EODENTIA 



tending to disappear, in some species without trace of lirst 

 lamina ; upper incisor compressed, set at such an angle that a 



I'pijer iUL-isiiis nf E/iimits (ri) ami Mi'n (b). 

 ilwh fiilargoil. 



sub-apical notcli is normally cut in its outer side b\' action of 

 lower tootli. 



Ilehtnrlis. - The genus Mils as now restricted contains the 

 Mus iiiiisi-iilioi group and the Asiatic and African species usually 

 referred to Lcg(jada. Though the species differ considerably 

 among themselves in details of structure the group is very 

 homogeneous as regards the yieculiar specialization of the 

 mechanics of the molars and the distortion of the first lamina 

 of ((/'. About twenty-live foi'uis are now known, seven of which 

 occLir in Europe. 



KEY TO THE EUROPEAN FOIOIS OF MUS. 



Hind foot broad and robust, its width at. base of 

 outer toes 4 to 6 mm. 

 Condylobasal length of skull in adults 21 -fj to 

 22 '2 mm.; hind foot 17-4 to IS -8 mm. 



(St. Kilda Island, Scotland) M. DiuvaUs, p 871. 



Condylobasal length of skull in adults 23 to 



23-'i mm; hind foot I'J to 20 ram. (Faeroes)... M. furocnsis, p. 875. 

 Hind foot narrow and slender, its width at base of 

 outer toes about 3 mm. 

 Tail about as long as head and body, often longer, 

 rarely much shorter ; colour of underparts 

 usually greyish, rarely contrasted with that 

 of sides ; condylobasal length of sliull fre- 

 quently more than 21 mm. ; hind foot usually 



17 to I'J mm. (House mice) J/, muxalus, p. 865. 



General colour dark and brownish, usually 

 without evidoiit yellowish tinge, the belly 

 dusky greyish (central and northern 



Europe) M- '". /-u«r»te, p. 869. 



General colour light, usually with a decided 

 yellowish tinge, the belly bulTy greyish 

 (Mediterranean region) M. m. (u-uriuus, p. 871. 



