612 RODENTIA 



External characters. — Form vole-like, slightly more robust 

 than in Microtus agrestls, the legs not shortened and feet not 

 enlarged as in Lemmiis lemmus. Head rather large, the anterior 

 portion blunt ; ear rounded, well developed, but nearly con- 

 cealed in the fur, reaching to within about 2 mm. of eye when 

 laid forward, the meatus with a distinct though not very high, 

 broadly triangular valve, both surfaces of ear thickly covered 

 with rather short hairs, a noticeable tuft of longer hairs at outer 

 base of meatal valve ; muzzle pad slightly developed, the upper 

 and inner margins of nostrils strongly projecting ; upper lip with 

 deep median cleft. Feet slender, strictly vole-like in form and 

 relative size, the claws on hind feet slightly larger and less 

 compressed than those on fore feet. Fore foot with the inner 

 digit essentially as in Lemmus lemmus, its strongly compressed, 

 strap-shaped nail extending to base of second digit ; outer digit 

 as long as second and a little less than half as long as the sub- 

 equal second and third ; pads four, well developed, essentially as 

 in the smaller voles, except that that at base of thumb is absent, 

 and postero-external is relatively larger and more elongated, its 

 extremity reaching nearly to level of tip of thumb-nail when 

 the two are approximated ; surface of palm between pads 

 granular-tuberculate, naked with a few scattered minute hairs. 

 Hind foot at least as slender as that of Evotomys glareolus, its 

 five tubercles relatively larger and more crowded, occupying 

 much more, than half the surface of the region in which they 

 occur, its digits with no special peculiarities of size or form ; sole 

 densely hairy behind pads, naked between them except for 

 a sprinkling of very fine hairs, the naked surface conspicuously 

 granular-tuberculate ; main tubercles sub-equal in size and 

 essentially alike in form except that the two hinderinost are 

 somewhat smaller and more tei'ete than the others, these two 

 nearly in contact, the outer slightly in front of the inner. Tail 

 short, but not unusually robust, densely covered with hairs that 

 nearly conceal the narrow, ill-defined annulations ; pencil slender, 

 about one-half as long as vertebra. Mammae : p 2 — 2 ; 

 i 2 - 2 = 8. 



Colour. — Except for the dorsal patch the entire animal is a 

 uniform dark grey approaching the slate-colour of Ridgway, the 

 upper parts with a slight steely effect due to the metallic, almost 

 silvery, appearance of the tips of the shorter hairs, and a less 

 evident dark "lining" produced by the longer wholly black 

 hairs ; a broad, rather ill-defined area on middle of back, 

 extending from shoulders to within about 15 mm. of base of tail, 

 a reddish brown intermediate between russet and rufous. Feet 

 and tail .slaty black, the hairs on under side of latter with a 

 strong silvery gloss. 



Skull and teeth. — Apart from their noticeably smaller size the 

 skull and teeth do not differ essentially from those of Lemmus 

 lemmus. The general outline of the skull when viewed from 



