The vizcachas are cleanly in their habits; and the fur, though it has a strong earthy smell, is kept exceedingly neat. The hind leg and foot afford a very beautiful instance of adaptation. Propped by the hard curved tail, they sit up erect, and as firmly on the long horny disks on the undersides of the hind legs as a man stands on his feet. Most to be admired, on the middle toe the skin thickens into a round cushion, in which the curved teeth-like bristles are set; nicely graduated in length, so that "each particular hair" may come into contact with the skin when the animal scratches or combs itself. As to the uses of this appendage there can be no difference of opinion, as there is about the serrated claw in birds. It is quite obvious that the animal cannot scratch himself with his hind paw (as all mammals do) without making use of this natural comb. Then the entire foot is modified, so that this comb shall be well protected, and yet not be hindered from performing its office: thus the inner toe is pressed close to the middle one, and so depressed that it comes under the cushion of skin, and cannot possibly get before the bristles, or interfere their coming against the skin in scratching, as certainly be the case if this toe were free as outer one. Again, the vizcachas appear to form the deep trenches before the burrows by scratching the earth violently backwards with the hind claws. Now these straight, sharp, dagger-shaped claws, and especially the middle one, are so long that the vizcacha is able to perform all this rough work without the bristles coming into contact with the ground, and so getting worn by the friction. The Tehuelcho Indians in Patagonia comb their hair with a brush-comb very much like that on the vizcacha's toe, but in their case it does not properly fulfil its office, or else the savages make little use of it. Vizcachas have a remarkable way of dusting themselves: the animal suddenly throws himself on his back, and, bringing over his hind legs towards his head, depresses them till his feet touch the ground. In this strange posture he scratches up the earth with great rapidity, raising a little cloud of dust, then rights himself with a jerk, and, after an interval, repeats the dusting. Usually they scratch a hole in the ground to deposit their excrements in. Whilst opening one of the outside burrows that had no communication with the others, I once discovered a vast deposit of their dung (so great that it must have been accumulating for years) at the extremity. To ascertain whether this be a constant, or only a casual habit, it would be necessary to open up entirely a vast number of vizcacheras. When a vizcacha dies in his burrow the carcass is, after some days, dragged out and left upon the mound.