[22] The jerboa when pursued can leap a distance of nine feet, and repeat the leaps so rapidly that it cannot be overtaken even by the aid of a swift horse. The bullfrog, a much smaller animal, can, when pressed, clear from six to eight feet at each bound, and project itself over a fence five feet high.
[23] The long, powerful tail of the kangaroo assists in maintaining the equilibrium of the animal prior to the leaps; the posterior extremities and tail forming a tripod of support.
[24] The rabbit occasionally takes several short steps with the fore legs and one long one with the hind legs; so that it walks with the fore legs, and leaps with the hind ones.
[25] If a cat when walking is seen from above, a continuous wave of movement is observed travelling along its spine from before backwards. This movement closely resembles the crawling of the serpent and the swimming of the eel.
[26] “On the Breeding of Hunters and Roadsters.” Prize Essay.—Journal of Royal Agricultural Society for 1863.
[27] Gamgee in Journal of Anatomy and Physiology, vol. iii. pp. 375, 376.
[28] The woodpeckers climb by the aid of the stiff feathers of their tails; the legs and tail forming a firm basis of support.
[29] In this order there are certain birds—the sparrows and thrushes, for example—which advance by a series of vigorous leaps; the leaps being of an intermitting character.
[30] The toes in the emu amount to three.
[31] Feet designed for swimming, grasping trees, or securing prey, do not operate to advantage on a flat surface. The awkward waddle of the swan, parrot, and eagle when on the ground affords illustrations.