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.