Genus II. ORYX. Type. _Oryx_, De Blainville, Bull. Soc. Philom. 1816, p. 75 O. gazella. Size medium or large. Tail with a long and thick terminal tuft. Hairs along the neck and spine with their points projecting towards the head, the parting being situated on the rump or behind the middle of the back. Skull with small lachrymal vacuities and of the same general structure as in _Hippotragus_; but the bases of the horns, instead of rising vertically above the eyes and forming an elevated forehead as in that genus, project straight backwards, continuing the line of the face and lying in the same plane as the nasal bones. Horns long, cylindrical, slender, straight, or with a gradual and gentle backward curvature, diverging at a very acute angle; ribbed in their basal half. _Female_ with horns as in the male. _Range of the Genus._ Africa south of the Sahara, except in the west-coast woodland and Congo Basin; also Southern Arabia. The five species of the genus here recognized may be arranged as follows:— _a._ Horns, when fully developed, crescentically recurved throughout. Neck and part of the shoulder to the base of the fore leg of a ruddy- brown hue and strongly contrasted with the yellowish-white tint of the body. 113. _O. leucoryx._ _b._ Horns normally straight or nearly so. Neck of the same colour as the body. _a1._ Size smaller (height about 3 ft. at the withers). Legs, with the exception of the pasterns, which are white, of a nearly uniform brown colour both outside and inside; body of a nearly uniform dirty white; no black spinal stripe, and only a faint throat-stripe; tips and edges of ears white; nearly the whole of the cheek beneath the eye covered with a large brown or blackish patch continuous with the ocular stripe; at most a faint brown stripe passing along the side above the belly; tail-tuft white at the base. 114. _O. beatrix._ _b1._ Size larger (height about 4 ft. at the withers). Colour of legs below knees and hocks pale dirty white, and lighter in tint than the body, though often patched with black in front; body and neck of a nearly uniform tawny hue, with a dark spinal stripe and a deep black throat-stripe; tips and adjacent edges of ears black; cheek below the eye of the same colour as the neck, bounded in front by the black ocular stripe and behind by a similar stripe running from near the base of the ear; a deep black stripe running along the side above the whitish belly; tail-tuft black.