MAMMALIA. 175 
account of the form of its claws and incisors. It is, indeed, intermediate between 
these very nearly allied sub-genera, with respect to its claws and teeth ; and its fur 
also is finer than that of the spermophilus Hoodiw, but less so than the fur of 
tamias Lystert. Its incisors are stronger and shorter, in proportion to its size, 
than those of the other marmots, but less compressed, and more slender than those 
of the squirrel. The claws likewise are rather more curved, and deeper at the 
base than those of the marmots ; but considerably larger, and not so sharp as the 
claws of a squirrel. The second toe from the thumb of the fore-feet is the 
longest, as in the spermophiles, and not the third, as in the squirrels.. Its ears 
very much resemble the ears of a ground squirrel, but are not so much pointed. 
IT have been able to collect no certain information respecting the manners of this 
little animal. Mr. Drummond obtained several specimens on the Rocky Mountains, 
in latitude 57°, and noticed that it burrowed in the ground. Lewis and Clark say 
that it is common to every part of the Rocky Mountains, where wood abounds. 
DESCRIPTION. 
Form of body, that of a spermophile or squirrel ; head, rather large ; legs, shorter than those 
of a squirrel. Jncisors yellowish, flattened anteriorly, and narrower behind, but not shewing 
the fine and numerous grooves which are visible when the incisors of the Sciurus Lysteri or 
quadrivittatus are viewed with alens. Mouth situated about as far back as that of Arctomys 
Hoodit. Forehead convex ; nose obtuse, covered with very short hairs, except a naked space 
round the nostrils. Whiskers black, shorter than the head. A few long black hairs over the 
eye, and on the posterior part of the cheek. yes, moderately large ; ears, rather larger in 
proportion than those of 4. empetra; but smaller than the ears of Sciurus Hudsonius or 
quadrwwittatus, consisting of a somewhat triangular flat flap, much rounded at the apex, placed 
on the upper or mesial side of the auditory opening, thickly clothed on both surfaces with 
short hairs, and having a small doubling of the anterior margin to form a helix, which, where 
it approaches the auditory canal, is covered with longer hairs. The fur on the back is dark 
at the roots, then pale-smoke-gray for a space, then brown, and, lastly, its tips are barred 
with white and dark hair-brown. The colour of the surface, when the fur lies smooth, may 
be termed a hoary brownish-gray. There is no vestige of a dorsal line. A yellowish-white 
streak commences close behind each ear, and running backwards along the sides, terminates 
at the hip. It is widest in the middle, being there three lines broad, and in some specimens 
it is very faint on the neck, though its commencement at the ear is always distinct. The white 
streak is hounded above and below between the shoulder and the hip by a pretty broad border 
of brownish-black. The sides under the lower black border, all the ventral aspect, the inner 
surfaces of the extremities, and the breast and throat, are of a soiled yellowish-white, some- 
