2 68 STUDIES IN THE EVOLUTION OF ANIMALS 



the Zebra ; it is striped not very unlike a Zebra or Quagga ; it has 

 long hair under its chin, which many cart-horses have ; its tail is 

 like that of a Horse ; the white-tailed Gnu shies exactly like a 

 Horse ; but this Gnu has a tuft of hair over its nose which is 

 unique, and may be somehow related to the horn on the nose 

 of the Rhinoceros, and which is stated to consist of an agglutina- 

 tion of hairs. 



The reader might say that the likenesses mentioned may 

 perhaps be conceded, but what about the horns of the ruminants ? 



{d) Well, in the Natural History Museum it is stated that ' The 

 earliest known forms of Deer, those of the lower Miocene period, had 

 no antlers, as in the young of the existing species. In the existing 

 genera, Moschus and Hydropotes, there are no antlers at any time. 

 The Reindeer has them in both sexes, and in all others the male only.' 



So we see there is a very great variation in these features, and 

 some existing genera among rummants, and also among extinct 

 forms of Deer, are itiitkout horns. 



Further, let us see what the great naturalists say about horns 

 in the Horse. 



(e) Darwin tells us,-' ' In various countries horn-like projections 

 have been observed on the frontal bones of the Horse ; in one case, 

 described by Mr. Percival, they arose about two inches above the 

 orbital processes, and were very like those of a calf from five to six 

 months old, being a half to three-quarters of an inch in length.' And 

 further on, Dr. Wallace says ' That horns have not unfrequently 

 arisen from such apparently uncaused variations is indicated by 

 the remarkable difference of structure and growth in the horns of 

 such allied groups as the Deer and the Antelopes, which at a quite 

 recent epoch must have originated independently.' 



^ ' Are individual acquired characters inherited ? ' by Alfred Russel Wallace, Fort- 

 nightly Review, April 1893, P- 495' 



