False Lemming Mouse 



In Alaska there occurs another lemming (Lemmns tn'mncronatus) 

 which is of a rusty colour and never changes white in winter. 



False Lemming" Mouse 



Plienacomys latimanns Merriam 



Length. 5.30 inches. 



Description. Strikingly like the meadow mouse in external ap- 

 pearance but with rooted molar teeth. Pale yellow cinnamon 

 brown above with an admixture of black hairs on the back, 

 below whitish gray; tail dark above, white below. 



Range. Known only from Ungava, Labrador and the north shore 

 of Lake Superior in Ontario. A somewhat larger species oc- 

 curs in Labrador and Quebec (P. celatus] and others in the 

 Northwest. 



The most interesting point 

 in the history of this rare 

 mouse is its close external re- 

 semblance to the meadow 

 mouse. For many years speci- 

 mens in the National Museum 

 passed as meadow mice until 

 Dr. Merriam discovered that 

 the back (molar) teeth did not 

 grow continuously from the 

 bottom as do those of the meadow mice, but possessed regular 

 roots as in the red-backed mice, a matter of small popular interest 

 but of great scientific importance as it shows us one more link in the 

 chain of evolution. Little is 

 known of the habits 

 Mr. 



Lower jaw of Plienacomys, enlarged, to 

 show rooted molar teeth. (After Miller.) 



mouse, though 



of this 



G. S. 



Miller, Jr., states that in 

 Ontario he found it frequent- 

 ing high upland barrens 

 covered with stunted blue- 

 berry bushes. Its burrow 

 was found running down 

 by a decayed stump and 

 terminating in a hollow, 

 evidently intended for the winter nest. Blueberries appeared to 

 constitute its principal food at this season. 



Lower jaw of Field Mouse, enlarged, to 

 show unrooted molars. (After Miller.) 



no 



