624 RODENTIA 



1900. Craseomys Miller, Proc. Washington Acad. Sci., ii, p. 87 (sub-gonus 

 of Evotomys : type Hypuclxus rufocanus Sundevall). 



1907. Craseomys Thomas, Proc. Zool. Soc, London, 1906, p. 8G3, April 11, 

 1907 (genus). 



Ti/pe species. — Mus rutilus Pallas. 



Geographical distribution. — Boreal portions of both hemi- 

 spheres ; south in Europe to the Pyrenees and the mountains of 

 southern Italy. 



Characters. — Bony palate terminating posteriorly in a simple, 

 thin-edged, horizontal shelf ; lower incisor with root extending 

 to outer side of molar-roots, but not rising above level of cutting 

 surface of molars and not forming any protuberance on outer 

 surface of ascending portion of mandible ; molars with two well 

 developed prongs or roots in adult, the crown disappearing by 

 wear in extreme old age ; pattern of enamel folding characterized, 

 as compared with that of other European voles, by a tendency 

 toward roundness or bluntness of the salient angles ; external 

 form without special peculiarities. 



Rcma7-Jis. — In the shortness of the mandibular incisor root, a 

 peculiarity which it shares with the American Phenacomys, the 

 genus Evotomys stands nearer to the Lemnii than any of the other 

 European members of the sub-family. Its rooted molars must 

 also be regarded as a primitive character, since the same 

 peculiarity is found in many of the related fossil genera. About 

 tifty forms are now recognized in the genus, thirteen of which 

 occur in northern Europe. These have recently been grouped in 

 three sub-genera,* two of which have even been regarded as 

 genera ; but the discovery of intermediate species makes this 

 course seem no longer tenable, f 



KEY TO THE EUEOPEAN FORMS OF EVOTOMYS. 



Tail densely haired, the pencil at least one-fourth 



as long as vertebrae (Arctic Europe) E. rutilus, p. 646. 



Tail moderately haired, the pencil much less than 

 one-fourth as long as vertebrte. 

 Skull of adult massive, its size large, the condylo- 

 basal length frequently more than 26 lum. 

 (25 to 27-6 mm.); teeth heavy, length of 

 tooth-rows 6 mm. or more. 

 Red of dorsal area conspicuously contrasted 

 with grey of sides ; ear noticeably over- 

 topping fur; vi^ normally without third 

 re-entrant angle on inner side (Northern 

 and mountainous portions of Scandinavia) E. rufocanus, p. 648. 



* True Evotomys, Craseomys Miller, and Phaulomys Thomas (Ann. 

 and Mag. Nat. Hist., 7th ser., xv, p. 493, May, 1905. Type Evotomys 

 smithii Thomas, from Kobe, Hondo, Japan). 



t For observations on the lack of distinctions between Phaulomys and 

 Craseomys see Anderson, Ann. and Mag. Nat. Hist., 8th ser., iv, p. 318, 

 October, 1909. For notes on the status of Craseomys see account of 

 Evotomys rufocanus, below, p. 658. 



