Moles display a high degree of instinct in the skilful construction of their subterranean fortresses. Their site is not indicated by those little mounds of loose earth, which we see raised up at night, and which mark their hunting excursions, but under a hillock reared by themselves, and protected by a wall, bank, or roots of a tree. The earth is well worked, so as to make it compact and hard, and galleries are formed which communicate with each other. A circular gallery is placed at the upper part of the mound, and five descending passages lead from this to a gallery below, which is of larger circumference. Within this lower gallery is a chamber, which communicates with the upper gallery by three descending tunnels. This chamber is, as it were, the citadel of the mole, in which it sleeps. A principal gallery goes from the lower gallery, in a direct line to the utmost extent of the ground through which the mole hunts, and from the bottom of this dormitory is another, which descends farther into the earth, and joins this great or principal road. Eight or nine other tunnels run round the hillock at irregular distances, leading from the lower gallery, through which the mole hunts its prey, and which it constantly enlarges. During this process it throws up the hillocks which betray its vicinity to us. The great road is of various depths, according to the quality of the soil in which it is excavated; it is generally five or six inches below the surface, but if carried under a stream, or pathway, it will be occasionally sunk a foot and a half. If the hillock be very extensive there will be several high-roads, and they will serve for several moles, but they never trespass on each other's hunting grounds. If they happen to meet in a road, one is obliged to retreat, or they have a battle, in which the weakest always comes off the worst. In a barren soil, the searching galleries are the most numerous, and those made in winter are the deepest, because the worms penetrate beyond the line of frost, and the mole is as active in winter as in warm weather. The females have a separate chamber made for them, in which they bring forth their young. This is situated at some distance from the citadel, and placed where three or four galleries intersect each other. There they have a bed made of dry grass, or fibres of roots, and four or five young are born at the same time, which begin to get their own food when they are half grown. Like all voracious animals, moles require a large quantity of water, consequently their run, or fortress, generally communicates with a ditch or pond. Should these dry up, or the situation be without such resources, the little architect sinks perpendicular wells, which retain the water as it drains from the soil.