174 THE WORLD OF LIFE 



on the left, which, with a general likeness of form, possess 

 individuality both in face-marks and in the curvature of the 

 horns ; while the two gazelles on the right are still more 

 distinct. The next group consists of three species of the 

 genus Cobus, in w^hich the horns are each so distinct in size 

 and curvature as to be easily recognisable at considerable dis- 

 tances ; the fourth figure shows the horns of the gemsbuck, a 

 very distinct species, not only in the body markings, but also 

 in the almost perfectly straight and very long horns. The 

 third group shows, at the top, the two species of kudu, the 

 horns of which, though exactly alike in spiral curvature, are 

 yet placed at such a different angle on the head as to be easily 

 distinguishable. The two lower figures are of animals not 

 closely allied, but, as one inhabits East and the other South 

 Africa, their ranges probably overlap each other, or once did 

 so. Here there is a somewhat similar bend in the horns, but 

 their thickness and direction render them absolutely distinct 

 from every point of view. 



^Now, as the antelopes are very closely allied to each other, 

 both in structure and external form, it seems improbable that 

 all the diversities in the horns (which are sometimes very 

 great in closely allied species) should have been acquired for 

 the sole purpose of fighting with each other or with an enemy. 

 But as these animals all possess markings on the head and 

 body which can only be interpreted as recognition-marks es- 

 pecially serviceable while in motion, it seems quite natural that 

 the horns should have been modified to serve the same pur- 

 pose while the animals are at rest, or when their bodies are 

 wholly and their faces partially concealed by the grasses or 

 bushes around them. 



The essential character of directive or recognition-marks 

 is strikingly shown by one of the best known of the African 

 antelopes — the springbok — which in the early days of the 

 Cape Colony swarmed over the whole of South Africa, even 

 in the vicinity of Cape Town. Its chief feature is thus de- 

 scribed in Chambers's Encyclopaedia : 



