184 CLASS MAMMALIA. 



The group is distinguished from others of the genus by 

 its large size, having long horns, common to both sexes : 

 they are slender, without ridges, sharp pointed, and black, 

 with annuli somewhat spirally turned about half or two 

 thirds of their length ; the ears are long; the eyes large, 

 dark, and prominent, the suborbital sinus almost obliter- 

 ated ; the nostrils ovine or without a muzzle ; the tail, 

 including the tuft, descends to the houghs, and the hoofs, 

 are mostly rather broad. The head is narrow if seen in 

 front, and rather square in profile, the horns following the 

 prolongation of the plane of the face ; the neck and withers 

 have the hair reversed in most species, and the shoulders 

 are rather elevated ; the legs are firm and well propor- 

 tioned, without tufts on the knees, or inguinal pores?; 

 the females have two mammae. A mane runs in general 

 along the ridge of the neck turned towards the occiput. 

 The general colours of the group are rufous-grays and 

 vinous yellowish upon a white ground, which predominates 

 more or less. All the species have a streak of white and 

 a darker next it, crossing the eyes, and upon the upper 

 arm and haunch. The species which frequent the woods 

 seem to have the hide of a white colour, as in Aigocerus 

 and those of sandy plains black, although the fur be pure 

 white. The calves are born of a reddish colour, which 

 becomes whiter as they grow up. As species or varieties, 

 this group is dispersed over an immense extent of territory, 

 perhaps from the borders of China, but certainly from the 

 Moultan, through Southern Persia, Arabia, over the deserts 

 of Northern and Middle Africa to Senegal, and south to 

 the Cape of Good Hope. Their great strength and swift- 

 ness, aided by their ability to feed on acrid succulents and 

 thorny shrubs, are sufficient to account for the vastness of 

 their native regions. 



They live in pairs : sometimes it is said the males have 

 two females, who with their young constitute families of 



