[35.] 1. Arvicola riparius. (O rd ? ) B a n k Meadow Mouse.
Genus, Arvicola. Lacepede. C u v i e r .
Arvicola riparius. Ord, Journ. Acad. Sciences Phil., volAv. p. 305 ?
Marsh Campagnol. Godman, Nat. H i s t vol. ii. p. 67.
A ( riparius ?) supra hepatico-irnnncus (esfusco fuligneoqui matis), sutler plumteus, auriculis mediocri.
buspilis obvelatis, cauda longitudine capitis, pedibus albidis.
Bank Meadow-mouse of a dull brown colour, intimately mixed with black; beneath bluish-gray: ears.,of a
moderate size, nearly hid by the fur; tail the length of the head; feet white.
It is so difficult to discriminate the different Meadow-mice by mere descriptions,
that I have much hesitation in referring any of my specimens to those which
have been named by authors. I have not had access to a museum containing
many species ; and their forms and colours differ so little, that figures, unless
very accurate, tend rather to mislead. Five species are common in the Hudson’s
Bay countries, exclusive of the lemmings; and there are doubtless others which
did not come under our notice. A considerable number have been described
as inhabitants of the United States by Rafinesque, Ord, and others; but the
American naturalists are by no means agreed about the species, and have applied
the names variously. The Meadow-mouse which I have referred to Mr. Ord’s
riparius, corresponds with the short account by that author in the Journal of
Science; but the description of Mr. Ord’s specimen by Dr. Harlan, in his Fauna
Americana, under the name of Arvicola palustris,differs in several particulars,
and agrees more nearly with the Arvicola xanthognathus of the following article.
The animal which I am now about to describe was procured by Mr. Drummond,
near the fopt of the Rocky Mountains, Its manners are analogous to those of the
common water-rat (Arvicola amphibius), with which it may be easily confounded,
although the shortness of its tail may serve as a mark of distinction. It frequents
moist meadows amongst the mountains, and swims and dives well, taking at
bnce to the water when pursued. It is distinguished from the other American
species of this genus which have come under my notice, by the length and
strength of its incisors, which are twice the size of those of the Arvicola xanthognathus,
although the latter is the largest animal of the two.
DESCRIPTION.
Shape The head is rather large, and not easily distinguishable from the neck; the
incisors are much exposed, and project beyond the n o se; the upper ones are flattish ante
riorly are marked with some scarcely perceptible perpendicular grooves, and have a somewhat
irregular and rather oblique cutting edge; the lower incisors are twice the length of the
upper ones, narrower, slightly curved, and rounded anteriorly. Nose thick and obtuse,
JVhislcers black ; scarcely of the length o f the head. Eyes small, much concealed by the
fur. Ears moderately large, oval, rounded at the tip, covered on the outside with fur similar
to that on the neighbouring parts, and on that account not easily distinguishable until the fur
is blown aside. Body more slender posteriorly, the hind-legs not being so far apart as the
fore ones. Tail about the length of the head, somewhat flat horizontally, tapering, and thinly
covered with short hairs, which at the end form a small pencil-like point. Fore-legs short;
feet rather small, with four, slender, well-separated toes, and the rudiment of a thumb, which is
armed with a minute nail. Claws small, white, compressed, and pointed. The third toe
nearly equals the middle one, which is the longest; the first is shorter than these two, and the
outer one, which is the shortest of all, is half the length of the middle one. The hairs of the
-toes project over th e claws, but do not conceal them. The toes of the hind-feet are longer
th a n those o f the fore ones, and their claws are also somewhat longer. The inner one is the
shortest, the second is longer than the third, and the third than the fourth; but the difference
between the three is but ju st perceptible. The first and fifth are considerably shorter than
the others, and are situated further back. The first, or inner one, which is the smallest, from
its shortness and position, resembles a thumb. The hind toes are turned a little inwards, as
is usual in the meadow-mice; but there is no provision either of webs or the arrangement of
th e hairs to give them much power in swimming.
The fu r on the back is about eight lines long, but not so soft and fine as in some others of
•the genus ; it is nearly as long on the crown of the head and cheeks; but it is shorter and
thinner on the chest and belly. The specimen described was killed in summer; in the winter
perhaps the fur may be of a better quality.
Colour—Incisors yellow. The whole dorsal aspect, including the shoulders and outside of
th e thighs, is of a dull, dusky, dark brown, proceeding from an intimate mixture of yellowish-
brown and black. These colours are confined to the tips of the hairs, and are so mingled as
to produce a nearly uniform shade of colour without lustre. From the roots to near the tips
the fur has an uniform shining blackish-gray colour. The ventral aspect is bluish-gray. The
margin of the upper lip, the chin and feet, are dull white. The tail is dark-brown above and
whitish beneath, the two colours meeting by an even line.
Dimensions.
In ch e s.
Length of head and body , » 7
ix tail . , 2
The depressed or flat tail may cause this animal to rank with the Mynomes of
Rafinesque; but it is certainly not the same with the Meadow Mouse figured in
Wilson’s Ornithology, plate 50, with which Desmarest (Mamm. p. 286) unites it.