210 MICROTIN^ 



Type locality. — " Rocky Mountains, inhabiting Ali:)ine swamps 

 in latitude 56° " (Richardson). " Near the headwaters of one 

 of the southern tributaries of Peace River, or between there 

 and the Jasper House region," Alberta, Canada (Preble). 



Range. — Unknown. 



Characters. — Essential characters as in other members of the 

 genus. General colour, in the type a young adidt changing 

 into winter pelage, reddish-orange, palest on the ventral aspect; 

 interspersed with a number of longer black-tipped hairs on back 

 and sides. Black hairs more numerous on upper part of head, 

 around the eyes, and on the nape, the fur in these places having 

 a mixed black and orange colour. Nose greyish-brown; sides 

 of face pale orange ; upper lips white. Feet brownish. Tail 

 coloured like the body. Fur on body about 19 mm. long, very 

 short on nose and extremities. 



Skull broken; but its characters apparently and those of 

 the teeth essentially as in other species of Lemmus. 



For external and cranial dimensions, see tables at end of 

 volume. 



Remarks. — This species is still apparently only represented 

 by the type, but it is not improbable that when further material 

 comes to hand from Alberta L. helvolus will be found to be identical 

 with one or other of the forms described from western North 

 America in recent years. Preble {loc. cit.) says : — " Though 

 specimens referred to Lemmus helvolus have recently been 

 recorded from Cassiar Mountains, Telegraph Creek, and other 

 points in northern British Columbia, this region is so far from 

 the actual type locality of helvolus that the specific identity of 

 the specimens must at present be considered merely as 

 assumptive." 



Group: MICROTI. 



Lower incisor long, its alveolus extending backwards at least 

 to the base of the condylar process, lingual to m^ and m^, labial 



to W3. 



Genus : 5. EVOTOMYS Coues. 



1811. Myodes Pallas, Zoograph. Rosso-Asiat., 1, p. 173 (in part; 

 genus based upon Mus lemmus Linn., and therefore antedated by 

 Lemmus Link, 1795). 



1814. Brachyurus Fischer, Zoognosia, ed. Ill, 3, p. 55 (in part). 



1831. Hypudceus (with misprints liypudacus, and Hypudeus, Mehlis, 

 Oken's Isis, 24, p. 874 (genus based on H. hercynicus Mehlis = Mus 

 glareolus Schreber); Keyserling and Blasiiis, Die Wirbelthiere 

 Europas 1840, pp. viii and 34 (subgenus). Not of lUiger, 1811. 



1839. Myodes de S^lys-Longchamps, ;fitudes de Micromamm., p. 87 

 (group). 



