THIS little animal has most wonderful powers of reproduction, and, as it is extremely voracious, it often causes an amount of destruction quite out of proportion to its size and insignificant appearance. It burrows in the ground, like the lemming and water-rat; and as it gnaws through the roots of trees that lie in its way, it has been known to cause very serious loss of property. In the year 1813 such immense numbers of these creatures were collected in some of the forests of the South of England, that it was feared all the young trees would be destroyed, and it was found necessary to organise a war of extermination against the invaders. It is said that in New Forest alone not less than eighty or a hundred thousand mice were killed in one season, and the slaughter in other places was quite as great. The Field-Vole’s favourite food is the bark of trees and roots, but, if pressed by hunger, it will attack and devour its own kind. [Illustration: THE JERBOA. (_Dipus ægyptius._)] THE principal peculiarity of this animal consists in its having very short fore legs, and very long hinder ones: a bird divested of its feathers and wings, and jumping upon its legs, would give us the nearest resemblance to the figure of a Jerboa when pursued. It uses, however, all its four feet upon ordinary occasions, and it is only when pursued that it presses its fore feet close to its body, and leaps on its hind ones. The ancients called it the two-footed rat. This creature is about the size of a rat; the head resembles that of a rabbit, with long whiskers; the tail is ten inches long, and terminated by a tuft of black hair. The fur of the body is tawny, except the breast and throat, and part of the belly, which are white. The Jerboa is very active and lively, and jumps and springs, when pursued, six or seven feet from the ground, with the assistance of its tail; but if this useful member be in any manner injured, the activity of the Jerboa is proportionately diminished; and one which had been accidentally deprived of its tail, was found unable to leap at all. It burrows like the rabbit, and feeds like the squirrel: it is a native of Egypt and the adjacent countries, and is also found in eastern Europe. [Illustration: THE CHINCHILLA. (_Chinchilla lanigera._)]