The true Squirrels, which may be regarded as the types of this family, are distinguished by their slender and graceful forms, and their long and generally bushy tails, the latter character having originated their classical name of _Sciurus_, as a compound of two Greek words, indicating their habit of carrying their tails thrown up, so as to shade the back. Our COMMON SQUIRREL (_Sciurus vulgaris_) may serve as a good example of this division of the family. It is too well known as a pet to need any detailed description; its elegant form and graceful movements, the rich brownish-red colour of its upper surface, contrasting with the white of the belly, and the beautifully-pencilled or tufted ears, which, combined with its bright black eye, give it such a lively appearance, must be familiar to every one. When full-grown, the Squirrel measures from eight to ten inches in length of body, and has a tail seven or eight inches long. British specimens are generally smaller than those from the Continent of Europe. It varies considerably in colour with the seasons, especially in northern regions; but even in Central Europe and in Britain the fur of the sides and back becomes mixed with a certain quantity of greyish-white hairs in the winter, whilst in Lapland and Siberia the whole upper surface acquires a grey tint at that season. In the summer also the ear-tufts diminish, or altogether disappear. In the Alps and Pyrenees, there is a variety having the back of a dark brown colour, speckled with yellowish-white. This has been described as a distinct species, under the name of _Sciurus alpinus_. The Common Squirrel is a widely-distributed species. It is abundant all over Europe, except, according to Pallas, in the Crimea, and extends beyond the Ural Mountains through the whole length of Southern Siberia to the Altai and the Amoor region. It occurs in the Caucasus, and probably in Persia. Everywhere it haunts the woods and forests, living chiefly upon the trees, among the branches of which it displays the most astonishing agility. On the ground--to which, however, it does not often descend--it is equally quick in its movements. If alarmed under these circumstances, it dashes off to the nearest tree with lightning-like rapidity, and by the aid of its sharp claws rushes up the trunk till it has reached what it considers a safe elevation, when the little sharp face and bright eyes may be seen peeping at the intruder, apparently in triumph over his supposed disappointment.