THE HOOFED MAMMALS. 153 



dark central patch on the muzzle. The gland below the eye is small and 

 concealed by hair, and the knees generally carry tufta of long hair. The 

 springbok (&. euc/iore), remarkable on account of its habit of taking leaps in 

 the air, and also from the enormous herds in which it was formerly found, 

 differs from all the rest of the gazelles in having an erectile crest of long, 

 stiff, white hair running down the back. Clarke's gazelle {AmmoAorcai 

 clarkei), from Northern Somaliland, is distinguished by the regular upwards 

 and forwards curvature of the horns of the males, which are ringed in part at 

 the base ; the females being hornless. The skull is intermediate between that 

 of the preceding and following genus. Waller's gazelle {LUliocranius walleri), 

 which is an East African form ranging from tlie Kilimanjaro district to 

 Somaliland, represents another genus by itself. The females are hornless, 

 but in the males the horns are erect and curved forwards in a hook-like 

 manner ; while both are characterised by the extraordinary neck, which 

 gives to the animal almost the appearance of a small giraft'e. The genus is, 

 however, best characterised by the solid structure of the skull. The small 

 Somali Dorcatragus seems to be another aberrant gazelle. 



The next group of antelopes, which are common to Africa and Arabia, are 

 best characterised by the upper molar teeth being structurally similar to 

 those of the oxen. In these teeth the crowns are very tall and broad, 

 so as to form an almost square section, while, on their inner side, they 

 have a narrow additional column superadded to the four large normal cres- 

 centic ones. All these antelopes- are of very large size, and both sexes are 

 provided with long horns, which are placed innnediately over or behind 

 the eyes, and are recurved, straight, or subspiral in form. The muzzle 

 ia hairy, there is no gland below the eye, and the long, cylindrical 

 tail is tufted at the extremity. In the skull there are no distinct pits on the 

 forehead, there is no depression below the eye, and only a very small 

 unossified slit in the same region. The handsome recurved horns, rising 

 vertically from a crest above the eyes and sweeping backwards in a scimitar- 

 like sweep at an obtuse angle to the profile of the face, serve at a glance 

 to distinguish the sable-antelope {Hippotrayus niger) of South Africa and 

 its near ally the roan antelope {H. 

 eqiUnus). In both these large and 

 splendid animals, as well as in a 

 kindred species from the Sudan, the 

 horns are ringed nearly to their tips, 

 the sable-antelope being one of the 

 few members of the tribe which have 

 the whole upper-parts, save some white 

 streaks on the face, a deep, full black. 

 In all these antelopes the neck is 

 furnished with an erect or curving 

 mane, and the tip of the tail is strongly 

 tufted. The gemsbok of South Africa 

 ia the type of an allied genus {Oryx), 

 ranging not only over the whole of J'^. 86. ^Sable-Antelope 



Africa south of the Saha*a, but also (^mppotrat/ux niger). 



found in Syria and on the shores of the 



Persian Uulf. Here the horns are long, slender, and ringed at the base, but 

 may be either straight or somewhat curved backwards, although in all the 

 species they arise behind the eyes with their direction at first iu the plane of 



