6 BATCHELDER — SOME JUMPING MICE [Fees 
Scotia. Contrary to what might have been expected, such 
material as I have seen from Halifax does not approach ardyi at 
all. Indeed it resembles canadensis so closely that I have found 
no characters by which it can be distinguished from that form. 
The representatives of Zapus hudsonius in the middle Atlantic 
States are strikingly different from either canadensis or hardyi, so 
much so, indeed, that, but for the existence of intermediates, one 
easily could be led to suppose them a distinct species,— a supposi- 
tion that might be strengthened by the slight variation displayed 
by specimens from quite remote localities. Examples from 
central Connecticut, for instance, are closely similar to others from 
North Carolina. 
The selection of a name for this subspecies is an easy matter. 
In 1799 Barton published’ an elaborate description of a jumping 
mouse “ which I discovered,” he says, “ near the river Schuylkill, 
a few miles from Philadelphia,” and which he named Dipus ameri- 
canus, His excellent description and definite statement of a type 
locality midway in the present known range of this subspecies, 
make the applicability of his name indisputable. It may there- 
fore stand as 
Zapus hudsonius americanus (Barton). 
Subspecific characters.—Zapus h. americanus is much smaller than Z. . 
canadensis, and both its hind and its fore feet are slenderer. The buffy color 
in its pelage is deeply tinged with reddish. The median dark area on head 
and back is much less pronounced than in cavadensis, being lighter and 
redder; this appears to be due to several causes: a larger proportion of the 
coarse hairs have their distal portion buff, the buff covers a greater extent of 
the individual hair, the brighter hue of the buff makes them more conspicuous. 
From similar causes the color of the sides has a less grizzled effect, and comes 
nearer to being a clear reddish buff. The buff of the sides encroaches more 
on the white of the under parts, which also is usually faintly tinged, occasion- 
ally strongly suffused, with buff. 
The skull is smaller than in canadensis. The rostrum is considerably 
deflected, and the skull in general is more arched longitudinally ; the cranium 
is much more rounded. ‘The molariform tooth-rows are more divergent. The 
audital bullz are less prominent, and their axes have a tendency to be less 
transversely directed to the axis of the skull. 
1 American Philos. Trans., IV, xii, pp. 114-120. 
