182 MICROTIN^ 



the colour is nearly uniform in both sexes at all seasons ; but 

 both the fur and the silvery hair-tips are a little longer in winter 

 than in summer. It seems to be a rare animal leading a retired 

 life in the dark recesses of the fir forests, and is usvially taken 

 only by accident, except m years of mouse-plague, when it becomes 

 somewhat more numerous. Its runs are found in moss under the 

 roots of trees or beneath fallen trunks. The food consists of mosses 

 (Dicranum), stems of red wortleberry, and the bark of juniper. 



2. Myopus morulus Hollister. 



1912. Myopus morulus Hollister, Smithsonian Miscell. Coll., 60, 

 No. 14, p. 1. 



Type. — U.S. Nat. Mus., No. 175,197; adult male, skin and 

 skull, collected August 16, 1912, by N. Hollister. 



Tj/pe locality. — Tapucha, 125 miles S.E. of Bijsk, Altai Moun- 

 tains, Siberia. Altitude, 6875 feet. 



Range. — -Known only from the type locality. 



Characters. — Size as in M. scJdsticolor ; hind-foot 16 mm.; 

 condylo-basal length 22-7. Colour darker and blacker; rusty 

 mantle duller but more extensive, extending forwards between 

 ears to crown of head, becoming more intense in colour posteriorly, 

 and broadening to cover lower back between hips. Face between 

 eyes, cheeks, sides, and imder 2>arts dark slate grey; the nose 

 slightly lighter. Hands like sides. Feet and tail black. 



Skull like that of M. schisticolor, but distinguished by its 

 smaller and much flatter bullae. 



Incisors weaker. Cheek-teeth compressed laterally, with 

 rounded enamel loops, and slightly smaller though of about 

 the same length as in M. schisticolor. 



For cranial and external measurements, see tables at end of 

 volume. 



3. Myopus saianicus Hinton. 



1912. Lemmus obensis Thomas, Ann. Mag. N.H., [8], 9, p. 401. 



Not of Brants, 1827. 

 1914. Myopus saianicus Hinton, Ann. Mag. N.H., [8], 13, p. 343. 



Type.~B.M., No. 12.4.1.126; adult male, skin and skull, 

 collected June 12, 1910, by Douglas Carruthers. 



Type locality. — Syansk Mountains, 100 miles west of Lake 

 Baikal, Central Asia. Altitude, 2200 feet; trapped "in wet 

 moss." 



Range. — Known from the Syansk Mountains and from the 

 forest area bordering the northern Gobi desert in Northern 

 Mongolia, whence it is recorded by G. M. Allen (Amer. Mus. 

 Nov., No. 133, 1924, p. 2). 



Characters.- — Size as in M. schisticolor, hind-foot 16 mm., 

 condylo-basal length 25-8 i- 



General colour considerably lighter and brighter than in 

 M. schisticolor, the rusty mantle more extensive, as in M. morulus. 



