MICROTUS 693 



protrudiug upper incisors. In immature specimens the skull is 

 strikingly like that of Pitymys suhterraneus, but when fully adult 

 the interorbital region becomes narrow and ridged, so that the 

 resemblance to Pitymys is lost. 



6, ?. Furka Pass, Switzer- Lord Lilford (p). 1. 11. 7. 13-14. 

 land. 



2. St. Gothard Pass. Purchased. 46. 6. 15. 44, 114. 



6. Engadiue (Fatio). E. R. Alston (p). 79. 9. 25. 51. 



6 al. Meran, Tirol, Aus- Dr. V. Fric (p). 90. 1. 30. 1. 



tria-Hungary. 



9 al. Paneveggio, Tirol. IMarquis G. Doria (p). 90. 3. 5. 15. 



MICROTUS ASTURIANUS Miller. 



1908. Microtus asturianns Miller, Ann. and Mag. Nat. Hist., 8th ser., i, 



p. 198, February, 1908. 

 1910. Microtus asturianus Trouessart, Faune Mamm. d'Europe, p. 181. 



Tyi)e locality. — Pajares, Leon, Spain. 



Geographical distrihution. — Austurias, and Sierra de Guadar- 

 rama, Spain. Details of distribution imperfectly known. 



Diagnosis. — Larger than Microtus arvalis (hind foot nearly 

 20 mm.), though similar in all general features. Skull massive 

 and deep, the dorsal profile strongly convex, the brain-case short 

 and broad, the zygomata widely spreading ; interorbital region 

 with evident ridges ; auditory bulke very large. Colour about as 

 in M. arvalis meridianus. 



Colour. — Upper parts buiiy clay-colour, rather coarsely 

 " lined " with black along median dorsal area, clearer and more 

 nearly approaching ochraceous-buff on sides ; underparts dull 

 grey, clear or washed with light buff; feet an indefinite bufly 

 grey tinged with drab, not conspicuously different from colour of 

 back ; tail obscurely bicolor, buffy grey below, brownish mixed 

 with grey above. 



Skull. — The skull is larger than in M. arvalis, its general 

 aspect so robust as to suggest that of a small M. orcadensis. 

 Zygomata widely spreading, strongly bent downward, not con- 

 spicuously widened at middle. Dorsal profile more strongly 

 convex than in any of the forms of arvalis, in this respect 

 resembling 31. cahrerse and M. liartingi ; this peculiarity is due 

 chiefiy to the great depth of the skull through interorbital 

 region. Brain-case short and broad, its general outline rather 

 more squarish than in M. arvalis, and suggesting that of 

 M. orcadensis. Auditory bullas relatively as large as in M. hartingi, 

 therefore noticeably exceeding those of true arvalis, and slightly 

 larger than those of levis. Palate normal. Nasals strongly 

 cuneate, not peculiar in form, and not in any way suggesting 

 those of 31. cahrerse, the posterior border sharply angular- 

 emarginate. Temporal ridges moderately developed. 



Teeth. — Except for their greater size, a character noticeable 



