624 RODENTIA 



1900. Craseoniys Miller, Proc. Washington Acad. Sci., ii, p. 87 (sub-genus 

 of Evotomijs : type Hupudivus rufocanus Sundevall). 



1907. Craseoniys Thomas, Proc. Zool. Soc, London, 1906, p. 863, April 11, 

 1907 (genus). 



Tjipe species. — Mus rutilus Pallas. 



Geographical distrihuiion. — 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. 



BemarJcs. — In the shortness of the mandibular incisor root, a 

 peculiarity which it shares with the American Phenaronnjs, the 

 genus Evotomijs 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, j 



KEY TO THE EUROPEAN FORJ^IS OP EVOTOMYS. 



Tail densely haired, the pencil at least one-fourth 



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



Tail moderately haired, the pencil much loss than 

 one-fourth as long as vertebra?. 

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

 basal length frequently more than 26 mm. 

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

 tooth-rows 6 ram. or more. 

 Red of dorsal area conspicuously contrasted 

 with grey of sides ; ear noticeably over- 

 topping fur ; vv' normally without third 

 re-entrant angle on inner side (Northern 

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



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

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

 sviithii Thomas, from Kobe, Hondo, Japan). 



t For observations on the lack of distinctions between Phaulomys and 

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

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

 Evotomys rufocanus, below, p. 658. 



