CHAPTER II.

THE DORMOUSE, LOPHIOMYS, RAT, AND MOUSE FAMILIES.

THE MOUSE-LIKE RODENTS--MYOXIDÆ--Characteristics--THE DORMOUSE--Description--Habits--Activity--Food--Winter Condition--THE LOIR--THE GARDEN DORMOUSE--LOPHIOMYIDÆ--How the Family came to be Founded--THE LOPHIOMYS--Milne-Edwards’ Opinion--Skull--General Form--Habits--MURIDÆ--Number of Species--Characteristics--Variety of Forms--Distribution--The Murine Sub-Family--THE BROWN RAT--History--Fecundity and Ferocity--Diet--At the Horse Slaughter-houses of Montfaucon--Shipwrecked on Islands--Story of their Killing a Man in a Coal-pit--In the Sewers of Paris and London--THE BLACK RAT--THE EGYPTIAN RAT--THE COMMON MOUSE--Habits--Destructiveness--Colours--THE LONG-TAILED FIELD MOUSE--Description--Food--THE HARVEST MOUSE--Description--Habits--In Winter--Agility--Their Nest--THE BANDICOOT RAT--THE TREE RAT--THE STRIPED MOUSE--Allied Genera--THE WHITE-FOOTED HAPALOTE--The American Murines--THE WHITE-FOOTED, OR DEER MOUSE--THE GOLDEN, OR RED MOUSE--THE RICE-FIELD MOUSE--THE AMERICAN HARVEST MOUSE--THE FLORIDA RAT--Description--Their Nest--Food--Mother and Young--THE BUSHY-TAILED WOOD RAT--THE COTTON RAT--THE RABBIT-LIKE REITHRODON--THE HAMSTERS--Characteristics--Appearance--Distribution-- Burrows--Disposition--Food--Habits--THE TREE MICE--THE BLACK-STREAKED TREE MICE--THE GERBILLES--Characteristics--Habits--Other Genera--THE WATER MICE--Characteristics--Species--THE SMINTHUS--THE VOLES--Characteristics--THE WATER VOLE--Appearance--Distribution--Food--THE FIELD VOLE--THE BANK VOLE--THE SOUTHERN FIELD VOLE--THE SNOW MOUSE--THE ROOT VOLE--THE MEADOW MOUSE--THE PINE MOUSE--THE MUSQUASH, MUSK RAT, OR ONDATRA--Distinguishing Features--Habits--His House--THE LEMMING--Description--Food--Habits--Disposition--Their Extraordinary Migrations--Other Lemmings--THE ZOKOR.

SECTION II.--MOUSE-LIKE RODENTS (_MYOMORPHA_).

The Myomorphic, or Mouse-like group of Rodents, includes a much greater variety of forms than the preceding, and the number of species is also very great. We find in it arboreal, terrestrial, and aquatic species; and in the second of these categories some presenting almost every variety of habit which the Rodent type is capable of assuming. Naturally the families and sub-families into which it is divided are rather numerous. Mr. Alston distinguished seven family groups, the first of which is the Myoxidæ.

FAMILY V.--MYOXIDÆ.

The Dormice, which constitute this family, have generally been regarded as nearly related to the Squirrels; and certainly, although they fall under the definition of the Myomorphic section, they have a plain affinity to the Sciuridæ. In form they are Squirrel-like, and the tail is long and hairy, although not so bushy as in the true Squirrels. They have four molars on each side in each jaw (_see_ figure), the front one in each series being smaller than the rest. All these teeth are rooted, and their crowns show transverse folds of enamel. The frontal bones are much narrowed; the fore limbs are small, with the thumbs rudimentary and furnished with a small flat nail; and the hind feet have five toes. The Dormice differ from all other Rodents by having the intestine entirely destitute of a cæcum. They are confined to the Eastern hemisphere, and chiefly to its temperate and colder regions; although a species of _Myoxus_, and some forms on which a special genus (_Graphiurus_) has been founded, inhabit Africa. The number of known species is only about a dozen.

The common DORMOUSE (_Myoxus avellanarius_) is an elegant little creature, about three inches long, with a somewhat bushy, cylindrical tail, two inches and a half in length. Its fur is of a light reddish-tawny colour above, becoming paler and yellowish on the lower surface. On the throat there is a small whitish mark. It is widely distributed in Europe, ranging from Britain and Sweden in the north to Tuscany and Northern Turkey in the south. Generally it is more abundant in southern than in northern countries, but in the south of France it is less common than either of the other two European species. Eastwards it does not extend beyond Galicia, Hungary, and Transylvania.

The Dormouse is nocturnal in its habits. During the day it sleeps in its nest or in some snug retreat, and at night comes forth in search of its food, which consists of nuts, acorns, seeds, berries, and the buds of trees and shrubs. It is particularly fond of the nuts of the common hazel, whence its specific name, and the name of “Haselmaus,” which it bears in Germany; these nuts it is said to pierce and empty without plucking them or taking them out of their cups. The Dormouse lives in small societies in thickets and hedgerows, where it is as active in its way amongst the bushes and undergrowth as its cousin the Squirrel upon the larger trees. Among the small twigs and branches of the shrubs and small trees the Dormice climb with wonderful adroitness, often, indeed, hanging by their hind feet from a twig in order to reach and operate on a fruit or a nut which is otherwise inaccessible, and running along the lower surface of a branch with the activity and certainty of a Monkey. Detached articles of food are held up to the mouth by the fore paws, after the fashion of a Squirrel. Towards the winter the Dormouse becomes exceedingly fat, and having collected a small store of food, makes for itself a little globular nest, composed of small twigs, leaves, pine-needles, moss, and grass, and within this, coiled up into a ball, passes into a torpid state.

Nevertheless, the winter sleep is not wholly uninterrupted; on mild days the Dormouse wakes up for a time and takes a little of its stored-up food. The female produces usually about four young, in the spring according to Professor Bell, in August according to Brehm; but the former writer thinks that in some cases two broods are produced in the year, as he has received from the same locality in September a half-grown Dormouse and three very young ones, evidently not more than a fortnight or three weeks old.

Of the other common European species, the LOIR (_Myoxus glis_) is found only in southern regions, its range extending from Spain to Southern Russia, and passing into the neighbouring parts of Asia. It is considerably larger than the Dormouse, measuring rather more than six inches in length, and has a bushy tail, in which the hairs are arranged in two rows, as in that of the Squirrel. The habits of this species are like those of the Dormouse. Fruit constitutes a portion of its diet, and it is said also to destroy and devour small birds and other animals. The Loir is a very voracious feeder, and becomes exceedingly fat in the autumn. By the ancient Roman epicures it was regarded as a dainty morsel, and they spared no pains to fatten it for the table. It sleeps during the day, and hibernates in some hole in a tree or in the ground, and the nest is formed in the former situation. The female usually produces about six young.

The GARDEN DORMOUSE, or LEROT of the French (_Myoxus nitela_), is common all over the southern and western parts of the Continent, extending northwards through Germany into the Baltic provinces of Russia. It is a little smaller than the preceding species, which, however, it resembles in its general habits; but it dwells commonly in gardens, and feeds on fruits, often doing much damage to the choicer varieties. It is a lighter and more active animal than the Loir, and is said to be even more predaceous in its habits. The female produces from four to six young, sometimes in a beautifully-made nest of her own, sometimes in the deserted or usurped nest of a Blackbird or Thrush, or in that of a Squirrel.

FAMILY VI.--LOPHIOMYIDÆ.

The importance of an animal in the zoological system by no means depends either upon its size or on its abundance in the world; its rank in the classification is decided solely by peculiarities of organisation which distinguish it more or less from its fellows; and in many cases the creatures which are regarded with the most interest by the naturalist are those which seem most to withdraw themselves from general observation. A single genus, perhaps containing only one or two species, may, by a singular combination of characters, be so completely isolated from all the recognised allied groups that it cannot be placed in any of them, and accordingly a distinct family, possibly even an order, has to be established for its reception. Sometimes subsequent discoveries add to the number of species forming the group thus set up, and in this way the prescience of its founder is confirmed. Sometimes the group remains in its original condition, leaving us, according to circumstances, to regard the anomalous creatures of which it is composed either as a special development of their general type, or as the residue of a group which may have presented a greater variety of forms at some past period of the earth’s history.

The latter is perhaps the case with the curious little Rodent which alone forms the present family, of which its original describer, M. Alphonse Milne-Edwards, writes as follows:--“In its general aspect it somewhat resembles certain Opossums, and like these it is pedimanous;[52] but these are the only analogies it presents to the Marsupials, and in its dental system, as also in the rest of its organisation, we easily see that it belongs to the order Rodentia. It differs, however, from all the members of this group by characters of considerable importance; I may even say that, by some peculiarities of structure it departs from all other Mammals, and that we find in it anatomical arrangements of which we have hitherto had examples only in the class of Reptiles.” After an exhaustive discussion of the characters of this curious little animal, M. Milne-Edwards comes to the conclusion that it is most nearly related to the members of the following family, and especially to the Hamsters, although he found it impossible to unite it with them. In this course he has been followed by other writers.

The general construction of the skull is the same as in the Muridæ, but from the temporal ridges thin plates are developed, which bend downwards, and articulate with similar plates springing from the malar bones, and thus completely arch over the temporal fossæ after a fashion only met with in certain reptiles, and especially in the Hawksbill Turtle (_Chelone caretta_). The whole upper surface of the skull is covered with minute but perfectly definite granules, arranged with much regularity, and these, which occur in no other Mammal, give the skull a very peculiar aspect, such as may be seen in some fishes. As in the Muridæ, there are three molars on each side in each jaw, and these are rooted and strongly tubercular; the foremost in each series having three and the others each two ridges. Without entering in detail into the peculiarities described at great length by M. Milne-Edwards, we may say that in its general structure, and especially in that of the skeleton, the animal is murine, but with a very important distinction, namely, that the collar bones, which are well developed in the Rats and their allies, are here reduced, as in the Hares and Rabbits, so as to form only two small bony styles freely suspended among the muscles, and that the first toe in the hind feet, although not very long, is so attached as to be opposite to the rest, thus converting the organ into a prehensile hand which the animal uses freely in climbing. The cæcum is small.

In its external characters this animal is as remarkable as in its anatomical structure. In general appearance, as stated by its describer, it has much resemblance to a small Opossum, but the bushy tail and the peculiar arrangement of the hair on the body are met with in no Marsupials. The head is small; the general form stout; the limbs short, and the hind ones not much longer than their fellows; and the ears are of moderate size and sparingly clothed with hair. The prevailing colour is blackish-brown, but a triangular spot on the forehead, a streak under each eye, and the tip of the tail, are white; and the long hairs which clothe the body and tail are dark only in the middle, the base and tip being white, as are also a great quantity of finer and shorter hairs which form a sort of under fur. But the chief peculiarity of the coat is to be found in the arrangement of the hairs of the body. The long hairs of the middle of the back and tail, some of which are nearly three inches in length, are capable of being raised into a nearly upright position, forming a sort of crest which gives the animal a very peculiar aspect, and this crest is separated from the pendulous hair of the flanks by a sort of furrow clothed with very peculiar hair of a greyish-tawny colour. These hairs are unlike any others known to occur among Mammals. The apical part is of the ordinary construction; but the following portion down to the base is “very rugose, and presents a spongy aspect, due to the interlacing, and, so to speak, felting of a multitude of epidermic filaments emanating from radiate cells, which constitute a perfect network of irregular meshes. Within the sort of sheath thus formed longitudinal filaments which break up into bundles of fibrils are to be seen.”

Very little is known as to the habitat of this animal, which M. Milne-Edwards has named _Lophiomys Imhausi_, the former name referring to the crested character of the back, the second commemorating the person who first brought the creature to the notice of naturalists. M. Imhaus, stopping for a few hours at Aden on his way home from Réunion, saw a living specimen of this Rodent in the possession of a negro from whom he bought it, but could learn nothing as to its origin. He inferred, however, that it had not been brought very far, and that its native country was either Southern Arabia, or some region in Abyssinia, or Nubia, on the other side of the Red Sea. This specimen was brought to France, and lived for about a year and a half in the Garden of Acclimatization in the Bois de Boulogne, where it fed upon maize, vegetables, and bread, slept during the day, and climbed with ease upon chairs and other convenient objects by the aid of its hinder hands. It never took its food in the fore-paws to carry it to the mouth as so many Rodents do. When irritated it elevated the crest right down to the end of the tail, and defended itself by biting vigorously.

It is doubtful whether the _Lophiomys_ inhabits Arabia, but it is found in the neighbouring parts of Africa. Professor Peters described the skull of the animal as representing a new generic type under the name of _Phractomys æthiops_. His specimen was obtained by Dr. Schweinfurth from the tombs of Maman, north of Kassala, in Upper Nubia. A third specimen has been brought from Keren in the Bogos country, and a fourth from the Erkanid mountains between Suakim and Singat.

FAMILY VII.--MURIDÆ.

We come now to the largest and most typical family of the Rodents: that, namely, which includes the Rats and Mice and their numerous allies. Mr. Wallace estimates the number of known species at 330, which is probably within the mark. All these forms agree in the following characters:--The lower incisors are compressed; the molars are usually three in number on each side in each jaw, in one genus only two in the lower or in both jaws, and in another four in both jaws. They are rooted or rootless, tubercular or flat, with folds of enamel; the malar bone is short and slender, generally reduced to a mere splint between the maxillary and squamosal processes of the zygomatic arch; the thumb is rudimentary, but often furnished with a small nail; and the tail is generally scaly, with a few scattered hairs, densely hairy only in a few species.

As might be expected in so large an assemblage of species, the variety of forms is very great among the Muridæ, but broadly, the common Rats and Mice, which are only too well known to most of us, may serve as characteristic types of the whole series. The family, however, includes jumping forms, swimming forms, arboreal forms, and burrowing forms, in which the peculiarities of the life-habits are very distinctly indicated by the external appearance of the creatures. In their distribution the Muridæ are almost absolutely cosmopolitan, the family being represented in every part of the world, with the sole exception of the islands of the Pacific Ocean. Australia possesses about thirty species of the family. New Zealand, at the time of its discovery, harboured a Rat, known as the Forest Rat, or Maori Rat, which was a favourite article of food with the natives, and is now almost extinct. It was proved by Capt. Hutton to be identical with the Black Rat (_Mus rattus_), and was probably introduced by the ancestors of the Maoris. Certain species also, such as the common Brown Rat and Mouse, are now perfectly cosmopolitan in their distribution, having accompanied man in all his migrations on the surface of the globe.

The Rat and Mouse form the types of a great sub-family, MURINÆ, which have the molars rooted and tuberculate when young, the infra-orbital opening high and perpendicular, widest above, and the lower root of the zygomatic maxillary process flattened into a perpendicular plate. They possess no cheek-pouches, have the fore and hind limbs approximately equal in length, the thumb rudimentary, and the tail nearly naked, covered with scaly rings. The genus _Mus_, to which our household pests belong, includes upwards of one hundred species, scattered over most parts of the Eastern Hemisphere, and living sometimes chiefly in the neighbourhood of human habitations, granaries, &c., where they often feed indifferently upon animal and vegetable substances, sometimes in the open country, and feeding almost exclusively upon the latter. The common BROWN RAT (_Mus decumanus_), sometimes called the Norway Rat, which is almost too well known to need description, is not a native of Great Britain, but was certainly introduced there by commerce, probably from some southern or eastern country--perhaps, as Pennant thinks, from the East Indies. Haunting ships in great numbers, it has now been introduced into all parts of the world, and it is quite impossible to ascertain its original habitat. It was known in Asia long before it made its appearance in Europe; and its passage into Russia is fixed by Pallas in the year 1727, when, he says, after an earthquake it swam across the Volga from the countries bordering the Caspian. Its first appearance in France and England is said to have occurred about the middle of the last century.

From its great fecundity and determined ferocity of disposition, the Brown Rat has become a great pest wherever it has taken up its abode. “It digs,” says Professor Bell, “with great facility and vigour, making its way with rapidity beneath the floors of our houses, between the stones and bricks of walls, and often excavating the foundations of dwellings to a dangerous extent. There are many instances of their fatally undermining the most solid mason-work, or burrowing through dams which had for ages served to confine the waters of rivers and canals.” It is almost impossible to keep them out of our houses, and, once in, there is no end to the mischief they do. Their ferocity is very great; and although they will, if possible, retreat from a powerful enemy, they will fight in the most savage fashion when they cannot escape.

Although not averse to a vegetable diet--as those who have to do with corn and seeds, whether in the field or the store-house, know to their cost--the Brown Rat evinces a decided preference for animal food, which he consumes of all kinds and in all states. The case of the horse slaughter-houses of Montfaucon, near Paris, is well known; here, the carcases of all the Horses killed during the day, sometimes to the number of thirty-five, would be picked to the bone by the next morning; and one main argument against the removal of the establishment to a greater distance from the city was that these swarms of ferocious vermin would be left without means of support, and would become a complete pest in the neighbourhood. That such an apprehension was not unfounded is proved by several instances recorded of the escape of Rats from wrecked ships upon small islands. In the course of a few years they exterminated every other living thing. Professor Bell, on the authority of the late Mr. Robert Stephenson, relates the following instance of the extreme ferocity of the Rat when driven by hunger:--“In a coal-pit,” he says, “in which many Horses were employed, the Rats, which fed upon the fodder provided for the Horses, had accumulated in great multitudes. It was customary in holiday times to bring to the surface the Horses and the fodder, and to close the pit for the time. On one occasion, when the holiday had extended to ten days or a fortnight, during which the Rats had been deprived of food, on re-opening the pit, the first man who descended was attacked by the starving multitude, and speedily killed and devoured.” Stories are also told, with what truth we do not know, of the occurrence of similar catastrophes in the sewers of Paris and London, where, as is well known, Rats abound.

The Brown Rat breeds several times during the year, and produces as many as ten, twelve, or fourteen young ones in a litter. Its general length is about nine inches. It may be distinguished from the old English Rat, which it has displaced in most localities, by its greyish-brown colour and by the comparative shortness of its ears, which, when pressed down, do not reach the eye.

The BLACK RAT (_Mus rattus_), or old English Rat, as it is sometimes called, agrees closely in its habits with the Brown Rat. It is smaller than the Brown Rat, measuring only about seven inches in length, but has a comparatively much longer tail and larger ears, which, when pressed forward, cover the eyes. Its colour above is greyish or brownish-black, and the lower parts are dark ash colour. Although the Black Rat has generally been compelled to give way before its larger and more vigorous competitor, it is still widely dispersed, but not in such numbers as formerly, in Europe. Its native country was probably Southern Asia. Nearly allied to it, if indeed specifically distinct, is the EGYPTIAN RAT (_Mus alexandrinus_). Both these Rats are said to keep more to the upper parts of houses than the Brown Rat.

Although the true Mice are very nearly allied to the Rats, of which they are copies on a small scale (and some of them, at any rate, are as destructive in their way as their larger relatives), they do not excite by any means the same sentiments of disgust with which Rats are generally regarded; ladies, indeed, will sometimes scream at the mere sight of a Mouse, but most of them will admit that, apart from its predatory habits, it is an elegant little creature. The COMMON MOUSE (_Mus musculus_) seems to be as completely associated with man as the Rat, and has accompanied him in his wanderings to all parts of the world. It is, however, said not to occur in the Sunda Islands. Of its general appearance and habits we need say nothing; they are too familiar to need description. But besides haunting our houses, the Mouse takes up its abode in the rick-yard, and here its devastations are often very serious. The Mice live in the ricks, through which they make passages in every direction, and their fecundity is so great that several bushels of Mice are often destroyed during the removal of a single rick. The Mouse breeds all the year round, and usually produces five or six young at a birth, so that its rapid increase under favourable circumstances is easily understood. Several varieties of the species are well known, especially the Albino form, or White Mouse, which is such a favourite pet with boys. The Common Mouse in England is sometimes patched with white, and we sometimes see in the shops Pied Mice, which are said to be of Indian origin. A pale buff variety is also sometimes met with; and during the removal of a rick some years ago, it was found to be infested by a breed of Mice with a naked wrinkled skin, to which the name of Rhinoceros Mice was given at the time.

Besides these more or less domestic species, there are in Britain two other representatives of the genus _Mus_, which do not generally frequent houses. One of these is the LONG-TAILED FIELD MOUSE (_Mus sylvaticus_), sometimes called the Wood Mouse, an exceedingly pretty little creature, rather larger than the Common Mouse, and having a proportionally longer tail. It measures about four inches in length, and the tail is about as long as the body; its colour is yellowish or yellowish-brown on the upper surface, whitish beneath; and the tail is brown above and white beneath. This species is found all over the temperate parts of Europe and Asia, living in the fields and gardens, where it takes up its abode, either in some small cavity under the root of a tree, in the deserted runs of the Mole, or less commonly in a little burrow excavated by its own labour. It feeds chiefly upon grain and seeds, of which it lays up a considerable store for winter use in its subterranean dwelling, and in this way does considerable damage to the crops. The Field Mouse does not, however, strictly confine itself to a vegetable diet, but under circumstances of privation will attack and devour smaller and weaker animals, not even sparing its own species. It breeds more than once in the year, and produces from seven to ten young in each litter. It is easily tamed, and soon becomes familiar.

The remaining British species, the HARVEST MOUSE (_Mus minutus_), is the smallest of the British quadrupeds, with the exception of the Lesser Shrew (_Sorex pygmæus_). The Harvest Mouse is to be found in most parts of England. It also occurs in Scotland as far north as Aberdeenshire; and in Ireland, but very rarely. On the Continent its range extends over nearly the whole of Europe, from Russia in the north to Italy in the south. It is well known in Siberia, and occurs abundantly in the steppes near the Caucasus.

The total length of this pretty little Mouse is about five inches, of which nearly one-half is made up of the tail. In it the eyes are less prominent than in the common Field Mouse, and the ears considerably shorter in proportion. Its colour on the upper surface is bright reddish-brown, and below pure white, the two colours being sharply separated. During the summer, the Harvest Mouse associates with the other Field Mice in corn-fields, and with them is very frequently carried in the sheaves of corn to rick-yards and barns, where it then takes up its abode for the autumn and winter, and, like other Mice, multiplies very rapidly, and no doubt does a good deal of mischief. The less fortunate individuals who are left behind in the fields retreat to little burrows for protection from the inclemency of the winter, which they pass in a state of at least partial torpidity; and to provide against exigencies they lay up in their dwellings a small store of food, to which they can have recourse when a fine day recalls them for a time to activity. Those which have been introduced into ricks and barns are, of course, liberally provided for, and they show their gratitude by remaining awake all the winter, as if on purpose to consume their abundant provender. In the open field their food consists of corn and the seeds of grasses and other plants, but also to a considerable extent of small insects.

In its movements the Harvest Mouse is wonderfully agile. On the ground it runs very rapidly; and it climbs upon shrubs and plants as cleverly as a Monkey, running out upon the thinnest twigs with the greatest confidence, and climbing up stalks of grasses so thin that they bend nearly to the ground with its weight. In these operations the long slender tail comes into use, as its extremity is prehensile, and can be twisted neatly round the small stalks and branches over which the little climber is making its way. From its lively habits, and the elegance of its form, the Harvest Mouse is a very interesting pet.

The Harvest Mouse breeds several times during the year, producing from five to eight or nine young at a birth, and provides for them one of the prettiest cradles formed by any Mammal. It is placed, according to the locality, upon several grass-leaves split and interwoven with the other materials, or suspended at a height of from eighteen inches to three feet above the ground, upon the twigs of some shrub or between several stalks of corn or strong grasses. It is egg-shaped, or nearly round, about the size of the egg of a Goose, and is composed externally of slit leaves of the reeds or grasses among which it is formed, each leaf being carefully divided longitudinally by the sharp teeth of the little architect into six or eight thread-like portions, which are then all woven together, so as to produce a firm structure. The interior is lined, or rather stuffed, with all sorts of soft vegetable substances, so that it has been a question with many observers how the mother could get at all the members of her family to suckle them, and how the nest could contain them all as they began to increase in bulk. The young usually remain in the nest until they can see; but as soon as they are able to provide for themselves, the mother takes them out, gives them some practical instructions in the art of living, and then leaves them to their own devices. According to Brehm, as these Mice increase in age they improve in the art of nest-building.

Besides these few species, a multitude of Rats and Mice, belonging to the same genus, occur as natives of nearly all parts of the world, but in their habits they agree in general with the British species. India harbours a considerable number, among which we may mention the BANDICOOT RAT (_Mus bandicota_), a large species, which inhabits the Indian and Malayan peninsulas, and is very destructive in plantations; and the TREE RAT (_Mus arboreus_), a native of Bengal, seven or eight inches in length, which lives partly on grain, of which it lays up stores in its nests, and partly on young cocoa-nuts, which constitute its favourite food, and in search of which it climbs the trees. This species builds a nest on cocoa-nut trees and bamboos, and occasionally makes predatory visits to the houses. The STRIPED MOUSE (_Mus barbarus_) is remarkable for its coloration, its ground colour being a bright yellowish-brown or reddish-yellow, adorned with several longitudinal blackish-brown streaks. This elegant Mouse inhabits Northern Africa, especially in stony places. It is very abundant in Algeria.

Nearly allied to the true Mice are numerous forms more restricted in their distribution, which have been formed into distinct genera. Thus _Pelomys fallax_, in which the incisors are grooved, the tail short, and the first and fifth toes of all the feet shorter than the three middle ones, is peculiar to Mozambique; _Acanthomys_, in which the fur is mixed with flattened spines, is an African genus; whilst _Echinothrix_, which has a somewhat similar coat, is Australian. Madagascar possesses two peculiar genera, _Nesomys_ and _Brachytarsomys_, the former having some relation to the American Murinæ, the latter remarkable for the shortness of the hind feet; and in Australia, besides the genus already mentioned, and one or two species of true _Mus_, we find the genus _Hapalotis_ represented by about thirteen exclusively Australian species. These animals have the hind limbs rather long, the ears large, and the tail long and hairy, terminating in a tuft. The molar teeth also exhibit a peculiar pattern; The best known species is the WHITE-FOOTED HAPALOTE (_Hapalotis albipes_), an animal about the size of the Brown Rat, of a smoky brown colour, with the belly and the feet white. It inhabits New South Wales, especially in the mountainous parts. The animals of this genus were formerly regarded as allied to the South American Chinchillas and Viscachas.

The American Murines all belong to a group to which the name of Sigmodontes has been given, because their molar teeth, which in the young state have two tubercles in each transverse row (instead of three, which is the usual number in the preceding forms), when ground down by use, show some S-like patterns in the enamel folds in place of transverse ridges. The greater number of the species belong to the genus _Hesperomys_ (Western Mouse), which is represented in both divisions of the American continent, and has been divided by authors into several sub-genera. The WHITE-FOOTED, or DEER MOUSE (_Hesperomys leucopus_) is perhaps the best known of all the species, and its varieties, or rather local permanent races, are distributed all over the continent of North America. The fur shows various brownish or greyish tints above; and the lower surface, with the feet up to the wrist and ankle, is snow-white. What Dr. Coues gives as the normal colour of typical specimens is a rich fawn, with a darker streak along the back: but he says that this is shown by not more than one example in six. The tail is generally white beneath. The length of the head and body is about three inches; the tail varies considerably in length. The White-footed Mouse is nocturnal in its habits, and feeds to a great extent upon corn, of which, with acorns and other nuts, it lays up stores for winter use. It lives a good deal upon trees, taking up its abode in the deserted nest of a Squirrel or of some small bird. When it constructs its own nest the little fabric is placed in a bush at from five to fifteen feet from the ground, and is very neatly constructed, usually of fine moss and strips of bark. In some localities it burrows in the ground. The GOLDEN or RED MOUSE (_H. aureolus_), which resembles the preceding species in form and size, has the fur of the upper surface golden-cinnamon colour, and the lower parts yellowish-white. It inhabits the Central and Southern States of the North American Union. The RICE-FIELD MOUSE (_H. palustris_), which has been placed in a distinct genus (_Oryzomys_), is a larger species, sometimes attaining the size of a small Rat. This is found in the Southern States, chiefly along the coast, and in rice-fields, where it is exceedingly abundant and does considerable damage. It is eminently aquatic in its habits. The AMERICAN HARVEST MOUSE (_Ochetodon humilis_) closely resembles the preceding species, but differs from them in a rather remarkable character. It has the upper incisor teeth grooved, a peculiarity which occurs also in the South American Rats of the genus _Reithrodon_. The American Harvest Mouse inhabits the Southern States, and extends northwards as far as Iowa and Nebraska.

The FLORIDA RAT, or Wood Rat (_Neotoma floridana_), is a widely distributed species in the United States, inhabiting especially the southern portion, but extending northwards as far as New York and Massachusetts. It measures from six to nine inches in length, with a tail from four to six inches long. In its coloration it presents a general resemblance to the common Brown Rat, but is brighter, especially on the sides; the lower surface is white. According to Audubon and Bachmann, the habits of this species vary considerably in different localities. These authors say that “in Florida they burrow under stones and the ruins of dilapidated buildings. In Georgia and South Carolina they prefer remaining in the woods. In some swampy situations, in the vicinity of sluggish streams, amid tangled vines interspersed with leaves and long moss, they gather a heap of dry sticks, which they pile up into a conical shape, and which, with grasses, mud, and dead leaves, mixed in by the wind and rain, form, as they proceed, a structure impervious to rain, and inaccessible to the Wild Cat, Raccoon, or Fox. At other times their nest, composed of somewhat lighter materials, is placed in the fork of a tree.” This species is very active and Squirrel-like in its habits. It feeds on grain, seeds, and fruits, and sometimes makes a meal of a Crayfish or a Frog. There are from three to six young in each litter, and two litters in the year. The young animals in very early days continue to adhere to the teats of their mother, even when she is walking about outside the nest, and even at a later period they will cling to her sides and back, after the manner of some Opossums. The female seems but little inconvenienced by this burden, and shows great affection for her family, defending them even at the risk of her own life. A nearly-allied, but smaller species, the BUSHY-TAILED WOOD RAT (_N. cinerea_), inhabits the western and north-western parts of America, also extending eastward to Hudson’s Bay, and southward to New Mexico and California. The COTTON RAT (_Sigmodon hispidus_), another inhabitant of the Southern States and Mexico, ranges southwards to Vera Cruz and Guatemala.

Besides several species of _Hesperomys_, South America possesses various Murine animals, which have been placed in special genera. Among these the most remarkable are those of which Mr. Waterhouse formed his genus _Reithrodon_, as these, although true Murines, have a very Rabbit-like character, and further present the peculiarity of having the upper incisors grooved. They have the profile much arched, the eyes large, the ears hairy, and the first and fifth toes of the hind feet very short. The tail is well clothed with hair. The RABBIT-LIKE REITHRODON (_R. cuniculoides_) inhabits Patagonia, where it was discovered by Mr. Darwin. It is of a yellowish-grey colour, mixed with black, with the throat and belly pale yellow, and the rump and feet white. The tail is about half the length of the head and body, dusky above, white beneath. The length of the head and body is six inches and a half. Two other species are described: one (_R. typicus_) from the La Plata; the other (_R. chinchilloides_) from the Strait of Magellan.

The HAMSTERS, forming the sub-family CRICETINÆ, are very nearly related to the true Mice and Rats, but differ from them at the first glance by their possession of large internal cheek-pouches, those organs being entirely wanting or very small in the Murinæ. Their molars, three in number in each series, are also tuberculate when young and regularly rooted. As age advances they become more and more worn away, so as to exhibit folds of enamel. They are stoutly-built rat-like animals, generally with short tails, with the upper lip cleft, and with short limbs, of which the hinder have five, and the anterior four, toes, the thumb being represented by a small wart. The Hamsters are confined to the Old World, and chiefly inhabit the temperate parts of Europe and Asia; two or three species occur in Africa. They live generally in corn-fields, where they dig deep burrows with numerous chambers, into which they can retreat to take their repose, and in which they pass the winter, previously, however, taking care to lay up a good store of provisions in some of the chambers of their domicile.

The best known species is the HAMSTER (_Cricetus frumentarius_, _see_ Plate 28), a rather pretty little beast, of about ten inches long, with bright, prominent, black eyes, short, membranous ears, and a tapering hairy tail, about two inches and a half in length. The fur, which is thick and somewhat lustrous, is usually of a light yellowish-brown colour above, with the snout, the neighbourhood of the eyes, and a band on the neck reddish-brown, and a yellow spot on each cheek; the lower surface, the greater part of the legs, and a band on the forehead are black, and the feet white. Many varieties occur. This Hamster is widely distributed, ranging from the Rhine, through Europe and Siberia, to the Obi; and in most localities where it occurs it appears in great numbers, and causes great injury to the crops. Its burrows are exceedingly spacious, and consist of numerous passages and chambers. In its temper it is exceedingly irascible, and at the same time very courageous, defending itself bravely against its enemies, and standing boldly on the defensive the moment any danger appears to threaten it. Its diet is by no means of a purely vegetable nature, but it will destroy and devour all sorts of small animals that come in its way. Besides the corn, which forms its chief winter provender, green herbage, peas and beans, and roots and fruits of various kinds, are welcome articles of diet, and in confinement it will eat almost anything.

The Hamsters pass the winter in their burrows in a torpid state, but waken up very early in the spring, generally in March, but frequently in February. At first they do not open the mouths of their burrows, but remain for a time subsisting on the stores laid up during the preceding autumn. The old males make their appearance first, the females about a fortnight after them, the latter about the beginning of April. They then set about making their summer burrows, which are not so deep or so complicated as the winter dwellings; and shortly afterwards the sexes pair. The young are produced twice in the year, in May and July; their number varies from six to eighteen. They have teeth when first born, and their development as babies is very rapid. Their eyes open in little more than a week after birth, and in another week they begin to burrow in the ground, and then their hard-hearted parent drives them off to take care of themselves.

The other species of this sub-family generally very closely resemble the Hamster, both in appearance and manners. Most of them are found in Central Asia and Siberia, extending southwards as far as Persia and South Tartary. _Cricetus songarus_ has been obtained at Kumaon. The recorded African species belong to two peculiar genera: they are _Saccostomus lapidarius_ and _fuscus_, and _Cricetomys gambianus_.

Other African forms constitute the small sub-family of the TREE MICE (_Dendromyinæ_), which are entirely confined to the southern portion of the continent. They are characterised by having the incisors rounded and grooved in front, the infra-orbital opening not narrow below, and the coronoid process of the lower jaw very small. The ears are clothed with hairs; and the feet, which are five-toed, are furnished with long claws, which are serviceable to the little rat-like animals in climbing up the trunks of trees. The BLACK-STREAKED TREE MOUSE (_Dendromys mesomelas_) is a rather pretty little species, of a greyish colour, with a black line down the middle of the back. It is slender in form, with a long, scaly tail, rounded ears, and the two outer toes in each foot shorter than the rest. _Steatomys pratensis_, from Mozambique, is stouter in form than the preceding, and has a short, densely hairy tail; and in _Lophuromys ater_, from the same locality, the incisors are not grooved, and the fur is developed into fine flattened bristles.

The GERBILLES (_Gerbillinæ_) are distinguished from all other Muridæ (although approached by _Hapalotis_) by the great length of the hind limbs, which are converted into powerful leaping organs, somewhat as in the Jerboas and Kangaroos, although not quite to the same extent. Like all the preceding forms, they have the molars furnished with roots, but not with tuberculate crowns, these being divided into transverse plates formed by separate elliptical or rhomboidal coats of enamel. The incisor teeth are narrow, the infra-orbital opening as in the Murinæ, and the tail long and hairy. The Gerbilles are plump little animals, with a short neck, a broad head, and a pointed muzzle. The feet are five-toed, but the thumb on the fore feet is reduced to a mere wart-like process with a flat nail. They are confined to the Eastern hemisphere, and, indeed, to the African continent, the south of Asia, as far as India, and the south-east of Europe, where they live both in cultivated districts and in the driest deserts, and often occur in great numbers, when they may cause considerable damage to the neighbouring crops. They shelter themselves during the day in shallow burrows, and come forth in the evening in search of their food, which consists chiefly of grain and roots. They store up great quantities of the ears of corn in their subterranean dwellings, and in many places the poorer inhabitants search after these stores, and by digging them out procure a good supply of grain. They are very prolific, the females producing large families several times in the year.

Several other forms of Muridæ, with rooted molars, have been distinguished, and all are inhabitants of the Eastern hemisphere. The genera _Phlœomys_ and _Nesokia_, each including a single species, form the group PHLÆOMYINÆ, characterised by having broad incisors and the molars divided by transverse plates of enamel. The characters of the skull are as in the Murinæ. _Phlœomys Cumingii_ is from the Philippine Islands; _Nesokia Griffithii_ inhabits Northern India. _Platacanthomys lasiurus_, the only known species of the group PLATACANTHOMYINÆ, resembles a Dormouse in its form, and is nearly allied to the preceding species, but has the fur of its back mixed with long, flattened, bristle-like spines. It is a native of the Malabar coast.

The WATER MICE (_Hydromyinæ_) are of particular interest, as being a small group, exclusively confined to the Australian region, and presenting the exceptional character among the Rodents of having only two molars on each side in each jaw. These teeth, are rooted, and divided into transverse lobes by ovate enamel lobes; the front tooth is much larger than its fellow. The _Hydromys_ are small rat-like animals of slender form, with long tails, rather densely clothed with short hairs, and short limbs. The hind feet have much stronger claws than the fore feet, and their toes are partially webbed. Five species of this group are known from Australia and Van Diemen’s Land, where they inhabit the banks of the streams. The best known are the Yellow-bellied and the White-bellied Water Mice (_Hydromys chrysogaster_ and _leucogaster_), both of which inhabit New South Wales, and the latter is also found in Van Diemen’s Land. The Sooty Water Mouse (_H. fuliginosus_) is an inhabitant of Western Australia.

In the SMINTHINÆ--a group which includes only the genus _Sminthus_, founded for the reception of a rat-like Rodent (_S. vagus_) first discovered in the Crimea, but now known to range from Hungary, Finland, and Sweden, through Russia to the banks of the Irtisch and Yenisei, and into Tartary (Bokhara)--we find another exceptional character of the molar teeth. There are four of these teeth on each side both above and below, the first and fourth of which are much smaller than the intervening ones. In this animal the ears are rather long and pointed, the legs are rather short, and the tail is about as long as the body, and clothed with short hairs.

In the remainder of the Muridæ, the molars, which are again only three in number on each side, are generally rootless, although occasionally the growth of the teeth stops and they close up below. The molars are composed of triangular prisms placed alternately. Two groups are thus characterised, namely, the Voles and the Zokors.

The VOLES (_Arvicolinæ_), which, next to the true Rats and Mice, form the most important group of Muridæ, are represented in the northern parts of both hemispheres. The brain-case in these animals is rhomboidal when looked at from above, the frontal region of the skull is much contracted, and the zygomatic arch stands out very far. The infra-orbital opening is as in the Murinæ. The molars are so constructed of alternating triangular prisms that the whole margin is enclosed by deep angular folds of enamel. These are mouse-and rat-like Rodents of a rather stout build, with the limbs and tail of moderate length, or short, and the latter more hairy than in the true Murines. The ears are short, often nearly concealed beneath the fur.

The true Voles (genus _Arvicola_) number about fifty known species, which have been arranged by various writers under a considerable number of sub-genera, generally corresponding to differences in mode of life. Three species, representing three of these groups, are found in Britain, and may serve to illustrate the natural history of the Voles. The largest of these is the well-known WATER VOLE, or Water Rat, as it is more commonly called (_Arvicola amphibius_), an animal rather smaller than the Common Rat, and having, like all the Voles, the muzzle considerably blunter, and the tail a good deal shorter and more hairy. Although thoroughly aquatic in its habits, the feet of the Water Vole are not webbed; they have five toes, but the thumb in the fore feet is very short. The general colour of the fur is reddish-brown, mixed with grey on the upper surface, and yellowish-grey beneath; the ears are nearly concealed in the fur; and the incisor teeth are deep yellow in front, and very strong, presenting a considerable resemblance to those of the Beaver, to which great Rodent the Voles were formerly considered to be related. It is very widely distributed, being found in all parts of Europe, and stretching right across Central and Northern Asia, to China, the Amoor region, and the Sea of Okhotsk. In Ireland, however, it is not found. Its habits vary a little in different localities, but in general it haunts the banks of rivers, in which it burrows to a considerable distance. In the water it is very active, swimming and diving with the greatest facility, and it is here that it seeks its food, which appears to consist exclusively of vegetable substances. Professor Bell says:--“A decided preference is shown, during the summer months, for the inner or concealed part of some species of sword-flags, which is very succulent and sweet-tasted. As this portion is usually below water, the animal gnaws the plant in two near its root, when it rises to the surface, and being conveyed to some sound footing, is consumed at leisure. In default of its more favourite food, it will make a satisfactory meal on the common duckweed. Only the green and fleshy leaf is eaten, the roots and other fibrous parts being rejected. While feeding on this plant, the creature sits like a Squirrel on its haunches near the water’s edge, and taking up a lump of the soft and slimy-looking mass in its fore paws, eats a small part only, and letting the remainder fall, takes up some more in the same manner.” The accusation sometimes brought against the Water Vole of eating worms and insects, and even of destroying fish-spawn, young fishes, and even young ducks, seems to be entirely unfounded. In the winter the Water Voles will feed on turnips, mangel-wurzel, and other roots, and also upon the bark of osiers and willows, to which they do considerable damage; and in some localities they appear to frequent gardens at all seasons of the year, burrowing in the ground, and feeding luxuriously upon the produce of the gardener’s labour. Their greatest activity is in the twilight, but in quiet situations they are to be seen abroad during the day. The female produces from two to six young at a litter: twice in the year in Britain, according to Professor Bell; three or four times in the course of the summer, according to Brehm and other Continental naturalists.

A second British species is the FIELD VOLE, or Short-tailed Field Mouse (_Arvicola agrestis_), which is less than half the size of the Water Vole, and has the tail only about one-third the length of the body, instead of half that length. In the general form of the head and body the two species are a good deal alike, but the ears project farther beyond the fur in the Field Vole. The general colour of this species is greyish-brown, becoming tinged with reddish or yellowish on the sides; the lower surface is pale grey or dirty white, and the tail is brown above and greyish beneath. The Field Vole is a very abundant species in the northern and central parts of Europe, but is wanting in Ireland and south of the Alps and Pyrenees. It is usually found in damp places, especially in meadows in the neighbourhood of woods and copses, where it forms burrows of considerable extent. Its food consists almost exclusively of vegetable substances, such as roots and herbage, and in times of scarcity it will climb up trees and bushes to feed on the tender parts of the bark. In case of necessity, however, it does not disdain animal food, but will eat insects and meat, and even sometimes kill and devour smaller individuals of its own species. It breeds three or four times in the year, producing from four to six young at a birth, in a small round nest made of moss and leaves, among the roots of the herbage in some hollow of the ground. Their increase, which would otherwise be very formidable, is checked by the smaller predaceous beasts and birds, such as the Weasel, the Kestrel, and the Owls, which destroy them in great numbers. The BANK VOLE (_Arvicola glareolus_[53]), the third British species, which is chestnut-coloured, with white feet and with a longish tail, closely resembles the preceding species in its habits, but feeds rather on fruits and roots than on herbage, and is far more addicted to a diet of animal food, freely devouring insects, worms, snails, and even young birds and carrion. It is pretty generally distributed over Europe, but not so uniformly as the Field Vole, which it even exceeds in fecundity, the females producing from four to eight young three or four times in the year, in a nest constructed of grass and moss placed in a hollow of the surface of the ground among dense herbage.

The Continent of Europe is inhabited by several other species of Voles, among which we may notice the little SOUTHERN FIELD VOLE (_Arvicola arvalis_), which more or less completely takes the place of our common Field Vole in Southern Europe, but also extends over the whole of Central Europe, and into Western Asia. Several of these species, and others to which we cannot specially refer, ascend to considerable elevations on the mountain-sides, but at least one species, the SNOW MOUSE (_Arvicola nivalis_), lives on the Alps and Pyrenees, at elevations of 4,000 feet and upwards, being most abundant about the limit of perpetual snow, where it not only resides during the short period of summer, when some portion of the surface is freed from its snowy covering, but actually throughout the winter, buried under the snow, through which it makes its way in search of the roots of plants. The ROOT VOLE (_Arvicola œconomus_) is a large and abundant Siberian species, the range of which extends from the Obi to Kamstchatka. This and some other northern species often migrate in great bodies, after the fashion to which we shall have to refer when speaking of the Lemmings.

In North America, it would appear from Dr. Coues’ monograph, there are about a dozen distinct species of Voles. One of them, confined to the northern parts of the Continent, he identifies with the _Arvicola rutilus_ of the Old World, which he regards as a circumpolar species. South of a line running from sea to sea, a little north of the boundary of the United States, comes another form, _A. Gapperi_, which is regarded as a sub-species of _A. rutilus_, to which _A. glareolus_ (_see_ p. 116) is considered to stand in a similar relation. The most abundant North American species is the MEADOW MOUSE (_A. riparius_), which is distributed, apparently, over the greater part of the Continent, and takes the place of the Field Vole. On the prairies there is a peculiar species (_A. austerus_), a sub-species of which (_A. curtatus_) is found in the Western territories as far as California; the PINE MOUSE (_A. pinetorum_) inhabits the country east of the Mississippi; and the genus is represented in Mexico by one species (_A. quasiater_). The Voles are most numerous and abundant in the northern and north-western parts of North America.

Another American species is the MUSQUASH, MUSK-RAT, or ONDATRA (_Fiber zibethicus_), which constitutes a genus distinguished from the true Voles by having the tail compressed and nearly naked, the hinder toes united by short webs, and fringed with long hairs, and the enamel folds of the molars united by a line running down the middle of the tooth. The form of the animal is thickset, and in this respect, as in its aquatic habits, it resembles the Beaver, to which it was formerly supposed to be nearly allied. The head is short and broad, the ears project very little beyond the fur, the hind limbs are longer than the fore legs, and terminate in five toes with strong claws, while the fore limbs have only four toes and a wart-like thumb; the fur is very thick and shiny, and the colour is usually brown above and grey below, with the tail, which is nearly as long as the body, black. The fur is well known in commerce. The length of the head and body of a full-grown male is about twelve inches. The name Musk-rat, often given to this species, refers to the musky odour diffused by the secretion of a large gland situated in the inguinal region.

The Musquash, which may be described as a large Water Rat, inhabits all the suitable parts of North America, from the thirteenth to the sixty-ninth degree of north latitude, and is most abundant in the Canadian region, which offers it peculiarly favourable conditions of life in the multitude of rivers and lakes, upon the banks of which the Musquash always takes up its abode. It is a nocturnal animal, passing the day in concealment, and coming forth with the twilight to seek its nourishment, and amuse itself with its fellows. In the water it displays wonderful activity, and, in many respects, presents much resemblance to the Beaver. Curiously enough, the parallelism of habits holds good to a certain extent, even in the construction of their dwellings. The Musquash generally lives in a burrow dug out of the bank of the stream in which he disports himself, and consisting of a chamber with numerous passages, all of which open under the surface of the water. But, under certain conditions, especially in the north, he builds himself a house of a rounded or dome-like form, composed of sedges, grasses, and similar materials, plastered together with mud, and supported upon a mound of mud of sufficient height to raise it above the water. The house contains a single chamber from sixteen inches to two feet in diameter, and is entered by a passage which opens at the bottom of the water. Other passages are said to issue from this, and to lead down into the ground under the bottom of the water; these are made by the animal in his search for the roots of water-lilies and other aquatic plants, which constitute a great part of his nourishment. The Musquash also seeks provisions on land, and in this way often does much mischief in gardens. Fresh-water mussels also form a part of its diet. It passes the winter in its house, which it then furnishes with a soft bed of leaves, grasses, and sedges, and, according to Audubon, ventilates by covering the middle of the dome only with a layer of similar materials, through which the air can pass. Of the propagation of the Musquash very little seems to be known with certainty. They pair in April and May, and the female produces from three to six young at a birth; but whether this takes place once or several times in the course of the summer is a matter of doubt. They are captured in fall-traps baited with apples, or by traps set at the mouth of their burrows. The Indians sometimes spear them in their houses.

The LEMMING (_Myodes lemmus_) is one of the most remarkable of the Muridæ, on account of the great migrations which it performs, apparently with no special object. In Norway, where it is best known, they make their appearance in the cultivated districts in such enormous numbers, and so suddenly, that the peasants have always believed them to fall from the clouds. The Lemming is a Vole-like animal, about six inches long, of which the tail makes up about half an inch. It varies considerably in colour, but is usually brownish-yellow, with dark spots above, and with a yellow streak enclosing the eye on each side of the face; the under surface is yellowish. The ears are very short, scarcely projecting beyond the fur; the eyes are small, black, and bead-like; the soles of the feet are hairy, and the claws of the fore feet much stronger than those on the hinder extremities. The Norwegian Lemmings live and breed among the peat mosses of the mountains. They are lively and active little creatures both by day and night, and feed upon the scanty vegetation of their Alpine home--grasses, lichens, the catkins of the dwarf birch, and roots. They are active even through the winter, when they make passages for themselves under the thick covering of snow which then veils the whole country, and thus are enabled to go in search of their ordinary food. They also make their way up to the surface, upon which they may occasionally be seen running, even in the depth of winter. They breed in their burrows and under stones, and must be very prolific, seeing that every predaceous animal in the country destroys and devours them. The Lemming is, in one sense, an exceedingly timid little creature, the slightest disturbance of its quietude, or even the passing over-head of a cloud, being sufficient to alarm it; but when attacked it displays the most dauntless courage, standing on the defensive against both men and animals, and biting very sharply at anything that comes within its reach. From time to time, from some unexplained cause, the Lemmings start in vast swarms from their mountain fastnesses, and make their way in a straight line in some definite direction. Nothing seems to turn them from their course; they go straight on, over hill and dale, and, although said at other times to have an aversion to water, they now swim across any lakes or rivers that come in their way. In this operation many of them lose their lives, for they require smooth water for their navigation, and the least breeze ruffling the surface suffices to send hundreds of them to the bottom. In this way they gradually arrive at the cultivated regions, where they do so much damage to vegetation, that in olden times a special form of prayer and exorcism was in use against them. Their march is accompanied by great numbers of carnivorous beasts and birds of all sorts. Wolves, Foxes, and Wild Cats, and the smaller quadrupeds of the family Mustelidæ, Eagles, Hawks, and Owls, all prey upon them with avidity--even the Reindeer is said to stamp them to death; and the story of his eating them, long discredited, has been confirmed on good authority, while man, with his Dogs and Cats, is not behindhand in the work of destruction. Nevertheless, a great multitude survives all these dangers, and, strange to say, the termination of this painful migration is always the sea, into which the survivors of the march plunge, and, apparently, voluntarily commit suicide. Mr. Crotch, who has published several papers on the Lemming and its migrations, says that in Norway these animals always proceed from the central backbone of the country in an east or west direction, and that in either case the survivors of the march drown themselves, those that go westward in the Atlantic, those that go eastward in the Gulf of Bothnia. His notion is that the migration is in obedience to an inherited instinct acquired at a time when there was land where the sea now rolls; but there are many difficulties in the way of such a hypothesis.

Besides the Scandinavian Lemming above noticed, several other species occur in the northern parts of the world. Three species (_Myodes lagurus_, _obensis_, and _torquatus_) inhabit Siberia; the latter two are found in North America, the last also in Greenland. In this species, which has been placed in a distinct genus under the name of _Cuniculus torquatus_, the third and fourth toes of the fore feet are much larger than the second and fifth (the thumb being rudimentary), and their claws become periodically enlarged to double their ordinary size by an enormous growth during winter of horny matter on the lower surface.

The transition from this to the next family is effected by two genera, which to such an extent combine the characters of the two as to have led different zoologists to place them sometimes in the one, sometimes in the other. Externally they have all the characters of the Mole-rats of the following family; in the characters of the skull and teeth they more resemble the Voles. The ZOKOR (_Siphneus aspalax_), which may be taken as an example of these forms, is an inhabitant of the Altai Mountains, has the eyes very small, the external ears reduced to mere rudiments, the body cylindrical, as in the true Mole-rats, and the fore-feet armed with very long and strong claws, of which that on the fifth toe is longer than the toe itself. This animal lives in subterranean runs something like those of the Mole, but of much greater extent, and in burrowing in the earth makes use of its strong incisors to cut through the roots it meets with, and when necessary to loosen the earth. The runs pass very near the surface, and are no doubt made for the purpose of feeding on the tender roots of grasses. A species of _Siphneus_ is said to occur in North China. The other genus (_Ellobius_) includes two species; one (_E. luteus_) from the country about the Sea of Aral; the other (_E. talpinus_) from south-eastern Russia and the west of Asia. The latter abounds in the Crimea. These animals form the sub-family Siphneinæ.