22 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
The variation in color is inconsiderable. It is chiefly found in the 
exact tone of the ground color, which may be more red or more gray 
than in the specimens described, and in the amount of shading of the 
back caused by the dark-tipped hairs. The exact extent of the 
rufous on the face is also variable. 
The ears are usually thickly furred, but in one specimen (No. 
4219, £ ad., Oct. 15,) they are less densely haired than usual, while 
in a very old female (No. 4221), taken on October 18, they are 
naked except for a few scattered hairs. 
In the female just mentioned there are eight mammae, four 
pectoral and four inguinal. 
The skull of Phenacomys latimanus never develops distinct 
interorbital ridges, even in extreme old age. It is in general 
characterized by weakness and lack of angularity. 
The enamel pattern is peculiar in the form of the front loop of the 
first lower molar. This loop is so deeply cut by the re-entrant angle 
on the inner side that it has the form of a hook with the concavity 
turned inward and is thus very different in form from the terminal 
loop of the back upper tooth. 
Peromyscus leucopus novebokacensis (Fischer). 
1829. Mus sylvaticus 8. Noveboracensis Fischer, Synopsis Mam- 
malium, p. 318. 
1830. Cricetus myoides Gapper, Zool. Journ., vol. 5, p. 204, pi. 10- 
1897. Peromyscus leucopus myodes Rhoads, Proc. Acad. Nat. Sci. 
Phila., p. 27. 
I did not find the common northern white-footed mouse at North 
Bay or on the north shore of Lake Superior. 
Mr. Brooks writes me that it is abundant at Milton and Mount 
Forest. 
Mentioned by Gapper as occurring in the region between York 
and Lake Simcoe. 
I have already recorded this species from Sutton, just south of 
Lake Simcoe. 1 
Mr. S.N. Rhoads has pointed out the characters which separate the 
northern and southern forms of the eastern Avhite-footed mouse. 
To the former he applies Gapper’s name myoides. Fischer’s Mus 
sylvaticus 8 . JVoveboracensis refers undoubtedly to the same animal 
and as noveboracensis antedates myoides it must be adopted. 
1 Proc. Biolog. Soc. Washington, June 20, 1893, vol. 8, p. GO. 
