False Lemming Mouse 
In Alaska there occurs another lemming (Lemmus trimucronatus) 
which is of a rusty colour and never changes white in winter. 
False Lemming Mouse 
Phenacomys lattmanus 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. cel/atus) 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 of this 
mouse, though Mr. 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 Phenacomys, enlarged, to 
show rooted molar teeth. (After Miller.) 

Lower jaw of Field Mouse, enlarged, to 
show unrooted molars. (After Miller.) 
Ito 

