174 MICROTIN^ 



Upper parts chiefly raw umber mixed with black ; lower parts 

 uniformly bluish-white ; feet and tail dusky. Ears medium, 

 partly hidden by long hairs growing from the anterior base; i 

 a conspicuous bluish-white side-gland is present in males. ' 



Skull differs from that of *S'. ivrangeli chiefly in its larger bullae ; 

 the other peculiarities mentioned by Merriam in his original 

 description stated by Osgood to be inconstant and to vary with 

 age. Cheek-teeth : m,^ and m^ each with the outer re-entrant 

 angle deeper than in S. wrangeli resembling the condition seen in 

 *S'. truci; m^ with small posterior loop. 



For external and cranial measurements, see tables at end of 

 volume. 



6. Synaptomys (Mictomys) wrangeli Merriam. 

 1896. Synaptomys {Mictomys) tvrangeli Merriam, Proc. Biol. Soc. 

 Washington, 10, p. 63. 



Type. — U.S. National Museum. 



Type locality. — Wrangel, Alaska. 



Characters. — -Similar to *S'. innuitus innuitus, but larger, with 

 the tail and hind-foot longer, and the skull narrower. 



Upper parts grizzled greyish-brown, with a yellowish cast; 

 under parts plumbeous, tipped with whitish ; tail bicoloured, 

 brownish above, whitish below, darker at tip. 



Skull narrower and less dejiressed than that of S. innuitus; 

 zygomata narrower and less spreading anteriorly ; braincase 

 narrower and less dejjressed ; auditory bullse less inflated an- 

 teriorly. Cheek-teeth : in^ with very small posterior loop ; 

 }/i.3 with outer fold shallower than in S. innuitus and enamel 

 folds of all teeth more loosely spaced. 



For external and cranial measurements, see tables at end of 

 volume. 



Remarks. — No material in collection. 



7. Synaptomys (Mictomys) andersoni Allen. 

 1903. Synaptomys {Mictomys) andersoni Allen, Bull. Amer. Mus. 

 N.H., 19, p. 554. 



Type. — -American Museum N.H. ; adult female. 



Type locality. — Level Mountain, northern British Columbia. 



characters. — Hind-foot 18 mm. 



Upper i^arts dark brown, faintly suffused with clay colour 

 and strongly varied with blackish ; under surface ashy grey, 

 rather sharply defined against the yellowish-brown flanks. Tail 

 black above, greyish on sides and lower surface. Upper surfaces 

 of paws blackish-brown ; hind-feet rather darker than fore-paws. 

 Ears small ; in autumn pelage wholly concealed in the fur. 



Skull much as in S. wrangeli, but bullae much more inflated, 

 especially anteriorly; m^ with a deep re-entrant outer fold; 



