44 THE PRINCIPLE OF CHAP. I. t keep one of their fore-legs donbled up for a long time, ready for the next cautious step; and this is eminently characteristic of the pointer. But from habit they be- have in exactly the same manner whenever their atten- tion is aroused (fig. 4). I have seen a dog at the foot of a high wall, listening attentively to a sound on the oppo- site side, with one leg doubled up; and in this case there could have been no intention of making a cautious ap- proach. Dogs after voiding their excrement often make with all four feet a few scratches backwards, even on a bare stone pavement, as if for the purpose of covering up their excrement with earth, in nearly the same manner as do cats. Wolves and jackals behave in the Zoo- logical Gardens in exactly the same manner, yet, as I am assured by the keepers, neither wolves, jackals, nor foxes, when they have the means of doing so, ever cover up their excrement, any more than clo dogs. All these animals, however, bury superfluous food. Hence, if we rightly understand the meaning of the above cat-like habit, of which there can be little doubt, we have a purposeless remnant of an habitual movement, which was originally followed by some remote progenitor of the dog-genus for a definite purpose, and which has been retained for a prodigious length of time. Dogs and jackals15 take much pleasure in rolling and rubbing their necks and backs on carrion. The odour seems delightful to them, though dogs at least do not eat carrion. Mr. Bartlett has observed wolves for me, and has given them carrion, but has never seen them roll on it. I have heard it remarked, and I be- lieve it to be true, that the larger dogs, which are prob- ably descended from wolves, do not so often roll in 15 See Mr. ~F. H. Salvin's account of a tame jackal in * Land and Water,' October, 1869.