[Illustration: FIG. 3.--Gemsbuck, or Cape Oryx (_Oryx gazella_).]
Gazelles (_Gazella_), which form by far the largest genus of the subfamily, are inhabitants of open and frequently more or less desert districts. They are mostly of a sandy colour, with dark and light markings on the face, and often a dark band on the flanks. The horns are more or less lyrate, and generally developed in both sexes; there are frequently brushes of hair on the knees. Gazelles may be divided into groups. The one to which the North African _G. dorcas_ belongs is characterized by the presence of lyrate or sub-lyrate horns in both sexes, and by the white of the buttocks not extending on to the haunches. Nearly allied is the group including the Indian _G. bennetti_ and the Arabian _G. arabica_, in which the horns have a somewhat S-shaped curvature in profile. In the group represented by the African _G. granti_, _G. thomsoni_, _G. mohr_, &c., the white of the buttocks often sends a prolongation on to the flanks, the horns are long and the size is large. Lastly, the Central Asian _G. gutturosa_, _G. subgutturosa_ and _G. picticaudata_ form a group in which the females are hornless and the face-markings inconspicuous or wanting.
The South African springbuck (_Antidorcas euchore_) is nearly related to the gazelles, from which it is distinguished by the presence on the middle line of the loins of an evertible pouch, lined with long white hairs capable of erection. It has also one premolar tooth less in the lower jaw. Formerly these beautiful antelopes existed in countless numbers on the plains of South Africa, and were in the habit of migrating in droves which completely filled entire valleys. Now they are comparatively rare.
The dibatag or Clarke's gazelle (_Ammodorcas clarkei_), of Somaliland, forms a kind of connecting link between the true gazelles and the gerenuk, this being especially shown in the skull. The face has the ordinary gazelle-markings; but the rather short horns--which are wanting in the female--have a peculiar upward and forward curvature, unlike that obtaining in the gazelles and somewhat resembling that of the reedbuck. The neck is longer and more slender than in ordinary gazelles, and the tail is likewise relatively long. Although local, these animals are fairly common in the interior of Somaliland, where they are known by the name of dibatag. In running, the head and neck are thrown backwards, while the tail is turned forwards over the back.