MOUSE  , in its

original sense probably the name of the semi-domesticated house-mouse (Mus musculus), the type of the genus Mus and of the family Muridae . Zoologically, there is no distinction between mice and rats; these names being employed respectively for most or all of the smaller and larger " mouse-like " and " rat-like " representatives of the Muridae, whether they belong to the genus Mus or not . It is true indeed that in zoological nomenclature some of these are distinguished as " voles " (see VOLE), but this is not in accord with popular usage, where such creatures come under the designation either of water-rats or field-mice . The distinctive characters of the typical mice (and rats), i.e. those included in the genus Mus, are dealt with in the article RODENTIA . With the exception of Madagascar, the genus Mus ranges over practically the whole of the Old World, having indigenous representatives even in Australasia; while the house-mouse, with man's involuntary aid, has succeeded in establishing itself throughout the civilized world . The following is a brief notice of the species of true mice (that is to say, those generally included in the genus Mus) inhabiting the British Isles . These are three in number . M. musculus, the house-mouse, originally a native of Central Asia, has spread to all the inhabited parts of the globe . M. sylvaticus, the wood or long-tailed field-mouse, is a species common in many parts of England, often taking to barns and out-houses for shelter during the winter . It is of about the same size and pro-portions as M. musculus, but of a bright reddish-grey colour, with a pure white belly . M. minutes, the harvest-mouse, is the smallest of the European mice, seldom exceeding 22 or 3 in. in length; and of a yellowish-red colour, with comparatively short ears and tail . It lives entirely away from houses, commonly taking up its abode in wheat or hay fields, where it builds a round grass nest about the size of a cricket-ball, in which it brings up its young .

Its range extends from England to

Japan . In regard to the first it is noteworthy that house-mice isolated on a small sandbank near Dublin have developed a special colouring of their own; also that distinct local varieties, M. musculus muralis and M. m. faeroensis, inhabit respectively St Kilda and the Faeroes . In Central Asia there exists a wild mouse (M. bactrianus), and likewise a second species (M. wagneri), with the habits of a house-mouse, both of which are closely allied to M. musculus; while there is a third kind (M. gentilis), also nearly related, in the deserts of North Africa . According to Major G . E . H . Barrett-Hamilton it is probable that M. bactrianus and M. musculus are respectively desert and house modifications descended from some Central Asian ancestor more or less nearly allied to M. wagneri . As regards the other two British species, it must suffice to say that there are several local races of each; Mus sylvaticus being represented by several in the British Isles, although there is but one British representative of M. minutus . It may be added that by some naturalists both M. sylvaticus and M. minutus are separated from Mus as Micromys . See G . E . H .

Barrett–Hamilton, "

Note on the Harvest-Mice of the Palaearctic Region," Annals and Magazine of Nat . History (April 1899) ; " On the Species of the genus Mus inhabiting St Kilda," Proc . Zool . Soc . (London, 1899) ; " On Geographical and Individual Variation in Ivius sylvaticus and its Allies," op. cit . (1900) ; W . E . Clarke, " On Forms of Mus musculus, with Description of a New Subspecies from the Faeroe Islands," Proc . Roy . Phys . Soc . (Edinburgh, 1904), vol. xv .

(R . L.*) MOUSE-

BIRD (Du . Muisvogel), the name by which in Cape Colony and Natal the members of the genus Colius of M . J . Brisson are known—probably from their singular habit of creeping along the boughs of trees with the whole tarsus applied to the branch . By the earlier systematists, Colius was placed among the Fringillidae; but the investigations of J . Murie and A . H . Garrod on its internal structure showed that it was not a true Passerine, and it is now placed in a separate family, Coliidae, amongst Coraciiform birds, near the trogons and swifts (q.v.) . The Coliidae are small birds, with a rather Mouse-Bird . finch-like bill, a more or less crested head, a very long tail, and generally of a dun or slate-coloured plumage that sometimes brightens into blue or is pleasingly diversified with white or chestnut . They feed almost wholly on fruits, but occasionally take insects, in quest of which they pass in bands of fifteen or twenty from tree to tree .

Seven species are believed to exist, all belonging to the Ethiopian region (of which the Family is one of the most characteristic), and ranging from

Abyssinia southwards . Three species inhabit Cape Colony . (A .