In the elegant symmetry of their form and the light and graceful agility of their motions, the Antelopes are superior even to the Deer, whom, however, they closely resemble, not merely in outward shape, but also in internal structure. Like them, in addition to the coincidence of a slightly made and beautifully proportioned figure, they are frequently furnished with a naked muzzle, and with the same remarkable sinus beneath the inner angle of the eye; and their ears are generally of considerable size, erect, and pointed. But they are strikingly distinguished from them and from all the other animals of the order by the peculiar character of their horns, which are formed of an elastic sheath enclosing a solid nucleus, and are for the most part common to the females as well as to the males. They have no canine teeth, and exhibit no appearance of a beard such as is seen in the Goats. The horns vary greatly in the different races; they are sometimes straight and upright, at other times slightly curved, and frequently spirally twisted with the most beautiful regularity: they are usually surrounded by elevated rings or by a spiral ridge, are constantly of the same form in the same species, and are not subject to an annual falling off and renewal, as in the Deer, from which they differ also in their mode of growth, the horns of the latter group lengthening at their apices, while those of the former receive their increase at the base. In their natural habits the numerous species of which this group is composed approach very closely to the Deer; there is, however, considerable variety in their mode of life. They inhabit almost every description of country; the sandy desert, the open plain, the thicket, the forest, the mountain, and the precipice, being, each in its turn, the favourite haunt of the different races; but, with the exception of a few species, they do not advance much beyond the limits of the tropics. The smaller ones usually prefer a solitary life, but the larger, for the most part, congregate together in herds, which are generally few in number. In their manners they exhibit much of that cautious vigilance and easily startled timidity, combined with a certain degree of occasional boldness and not a little curiosity, which are the natural consequences of their wild and unrestricted habits, of their trivial means of defence against the numerous enemies to whose attacks they are exposed, and of the unequalled fleetness of their speed. In some this latter quality consists of a continued and uniform gallop, which in others is interrupted at every third or fourth stroke by a long and generally a lofty bound, producing a beautiful effect by its constant and rapid recurrence.