M. amphibius, or the water rat, inha bits both the temperate and cold climates of Europe and Asia, frequenting the banks of rivers, in which it burrows. It stibsists on frogs, and roots and other ve getable substances ; swims with great speed, and can remain under water a con siderable time. It is more thick and short in its body than several other spe cies. It is never known to infest houses.
M. lemmus, or the leming. These ani mals are sometimes five inches long in the body, and in some countries (as Sibe ria) only three. They aboand in the mountainous districts of Norway and Lap land. In their general habits they are by no means particularly social; but reside in a dispersed manner, without skilfully contrived habitations, or storing up in magazines. On certain occasions, how ever, they descend from their elevated situations into the plains, in innumerable and formidable multitudes. Their direc tion is always in a straight line, from which nothing induces them to deviate but the absolute impossibility of proceed ing in it. Their track is visible by the destruction of herbage which attends it, the grass being devoured to its extreme roots, and their course exhibiting, instead of the greenness of vegetation the brown ness of a fallow. These migrations hap pen at irregular periods, generally after an interval of some years, and the perse verance and intrepidity with which they are conducted are matter of astonish ment. If attacked by men, they will spring at the legs of the assailants, and with great difficulty can be made to quit their hold. Thousands are destroyed in these progresses by birds of prey, and often the most formidable and fatal con flicts occur among themselves.
M. ceeonoraus, or the ceconomic rat, re sembles the leming in the circumstance of irregular migrations. These are met with, particularly in Siberia, burrowing with the greatest skill, and forming con siderable magazines of provisions (chiefly Various plants) for their winter consump tion, and which they occasionally pro duce, if damp, to dry them perfectly in the sun. They are about five inches and a quarter in their whole length. In their Migrations they swim over rapid rivers, preserving a course directly to the west, and experiencing extreme fatigue and peril, to which immense numbers of them become victims. A single party has been seen so numerous, as to take two hours in passing before the astonished specta tor. Scarcity of food is supposed the grand impulse of these progresses. The inhabitants of Kamtschatka are said to rob hoards of these animals in winter, pretending to make compensation by aving some childish toy behind. M. cricetus, or the hamster, is a species of the pouched rats, and the sole Euro. peen species of that description. The pouches are one on each side of the mouth, and, when filled, are like two blown bladders. These animals are found in Poland and Russia, and are extremely injurious by the quantities of grain which they devour, and also carry off for their autumnal store in their curious pouches. They are highly curious in the structure of their habitations. The females range their mansions differently from the males, and are stated never to reside with them. As winter approaches, they
seclude themselves completely, and enjoy their stores, which are generally ed when winter reigns in full rigour, about which time they roll themselves up, and continue till spring in a state of profound slumber, or torpor. Their dies are then said to be perfectly cold, and their limbs stiffened, and they may be opened without awaking them. The heart is seen to beat in them fifteen times in a minute, while in the summer its sations are 150 in the same time. fat is said to be coagulated, and the testines exhibit no excitability by the most stimulating applications. The ing of the hamsters from their ed sleep is a very gradual process, pying sometimes no less than two hours. These animals are unsocial, fierce, and malignant. They attack every weaker creature, and very frequently destroy each other.
M. musculus, or the common mouse, inhabits almost every part of the world, is shy and timid, but not ferocious in its temper. It produces generally from six to ten at a birth, and breeds several times in the course of a year. Its skin is sleek, and its eyes are bright and lively its limbs are neatly formed, and its move ments are extremely agile. It is occa sionally seen of perfect whiteness, and its appearance then is beautiful and interest ing. it haunts the habitations of man, from which it is scarcely ever found at any considerable distance, and in which it commits no trifling depredations.
M. sylvaticus, or the long-tailed field mouse, is somewhat larger than the for mer, and of a yellowish-brown colour. It feeds on acorns, fruits, and grain, and lays up magazines in its burrowed man sion for the winter. It is found princi• -pally in dry grounds ; is common in all the temperate regions of Europe, and is particularly abundant and destructive in France, where it is stated to commit more waste and havock than are effected by all other quadrupeds, and birds also. Under a scarcity of the usual supplies, these ani mals are supposed to destroy each other. Their stores in fruitful years are astonish ingly great, and nearly a bushel of nuts and mast is said to have been discovered in a single hole.
M. messorius, or the harvest mouse of Europe. is considered as the smallest of British quadrupeds, weighing only the sixth part of an ounce. Its nest is most artificially constructed, and platted of the blades of wheat, and is the size of a cricket ball, the opening to it being. clos ed up so skilfully as to be almost imper ceptible. Such is its compactness, that it may be rolled over the table without derangement. One found of this descrip tion, contained eight young, and appeared completely full without the dam, whose mode of access to it, so close and com pact as it appeared on every side, seem ed not easy to be explained. In the win ter these animals burrow deep in the earth ; but their favourite habitation is the corn stack.
For M. lineatus, or the lineated mouse, see Maim:India, Plate XVI. fig. 1.
For M. striatus, or the striated mouse, see Mammalia, Plate XVI. fig. 2.