FIELD BOOK OF MAMMALS 



Subgenus Mictomys 



Distinguished from the subgenus Synaptomys by cranial and 

 dental characters. 



Richardson Lemming Mouse. — Synaptomys horealis (Rich- 

 ardson) 

 "A dark, richly colored race, with foot somewhat short. 

 Skull rather small, . . . dorsal coloration rich and dark. 

 . . . Argus brown . . . plentifully mixed with black- 

 tipped hairs. . . . The tail is distinctly bicolor. . . . 

 Total length, 5.2 inches; tail vertebrse, i inch; hind foot, 

 .^2 inch." (Howell) Found in "The Athabaska-Macken- 

 zie region of Canada from Great Bear Lake south to near 

 Edmonton, and eastward (provisionally) to Lake Winni- 

 peg." (Howell) 



Dall Lemming Mouse. — Synaptomys horealis dalli (Merriam). 

 "A rather bright-colored race, with skull of moderate size. " 

 Upperparts Brussels brown mixed with blackish. Total 

 length, 5.2 inches; tail vertebrae, .8 inch; hind foot, .8 inch. 

 Found in "Hudsonian Zone in Alaska and south to central 

 British Columbia to the eastward of the coast district." 

 (Howell) 



Synaptomys andersoni Allen is said by Howell to be indis- 

 tinguishable from dalli. 



Chapman Lemming Mouse. — Synaptomys horealis chapmani 

 (Allen). 

 "A dark but dull-colored race with but slight dorsal tinge 

 of chestnut. Incisive foramina and rostrum long." Color 

 dull and gray, with some brown on rump ; tail faintly bicolor. 

 Total length, 5.2 inches; tail vertebrse, i inch; hind foot, .72 

 inch. Found in "Evidently the Canadian Zone of the 

 eastern portion of the southern half of British Columbia, 

 and adjacent mountainous slopes in extreme western 

 Alberta." (Howell) 



Wrangell Lemming Mouse. — Synaptomys horealis wrangeli 

 (Merriam). 

 "A race that is quite variable in coloration, with very low, 

 flat brain case, rather slender rostrum. ... In coloration, 

 ranging from skins that are a perfect match for the bright- 

 est, brownest dalli, to others that can not be told from gray 

 and grizzled specimens of chapmani, but the warmer tone 

 of color seems to be somewhat the more prevalent and to be 

 more typical of the unworn condition of pelage." Total 

 length, 5.3 inches; tail vertebra, i inch; hind foot, .64 inch. 

 Found in "Coastal strip in the Canadian Zone from the 

 Alexander Archipelago southward to the northern border of 

 the United States. " (Howell) 



Synaptomys truei Merriam is considered by Howell to be 

 indistinguishable from wrangeli. 



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