PITYMYS 753 



1896. Pitymys Miller, North American Fauna, No. 12, p. 58, July 23, 1896 

 (sub-genus). 



1907. Pitymys Mottaz, Bull. Soc. Zool. de Prance, xx, p. 27, September 

 1907 (genus). 



Type species. — Psammomys pinetorum Le Conte. 



Geographical distribution. — Central and southern continental 

 Europe, eastward into Asia Minor ; eastern and south-eastern 

 United States ; southern Mexico. 



Characters. — Like Microtus but sole with five tubercles, and 

 mammae only four ; external form slightly or considerably modified 

 for underground life ; skull in most species showing some trace 

 of fossorial modification, this character often conspicuous ; enamel 

 pattern variable, but first inner and first outer triangles of m 1 

 broadly communicating. 



BemarJes.- — The genus Pitymys is remarkable as the most 

 conspicuous instance of discontinuous distribution in the sub- 

 family. It is also the genus of European voles which presents 

 the greatest diversity of cranial and dental characters. All the 

 European members of the genus, twenty-five of which are here 

 recognized, may at once be distinguished from the other voles 

 occurring in the same region by the broad communication of the 

 first inner and first outer triangles of m v 



KEY TO THE EUROPEAN POEMS OF PITYMYS. 



Third upper molar longer than second, its inner side 



normally with three re-entrant angles subterraneus group. 



Dorsal profile of skull flat or faintly convex from 



nasals backward ; brain-case much depressed, 



its depth including auditory bullae about 65 



per cent of occipital breadth. 



Third inner re-entrant angle of m 3 shallow 



(Eoumania) P. dacius, p. 760. 



Third inner re-entrant angle of m 3 deep. 

 Back strongly suffused with buff y ; f eet whitish 

 in noticeable contrast with back (Basses- 



Alpes) P. druentius, p. 762. 



Back without noticeable bufiy suffusion ; feet 

 dusky, not noticeably contrasting with 



back P. subterraneus, p. 7 55. 



Brain-case moderately flattened ; colour 



dark (Belgium to Transylvania) P.s. subterranem,-p.758. 



Brain-case much flattened ; colour less 



dark (Puy-de-D6me region, Prance) P. s. capucirms, p. 760 



Dorsal profile of skull obviously convex from 

 nasals backward ; brain-case slightly de- 

 pressed, its depth including auditory bullse 

 about 70 per cent of occipital breadth. 

 Condylobasal length of largest skulls about 

 23 mm. ; dorsal profile of skull very slightly 

 convex (Neighbourhood of Zermatt, Swit- 

 zerland) P. falioi, p. 763. 



Condylobasal length of largest skulls about 

 25 mm. ; dorsal profile of skull noticeably 



convex (Northern Italy, &c.) P. multiplex, p. 764. 



3 c 



