THE HIPPOTIGRINE GROUP. 321 



sius, lib. Ixvii., relates that Caracalla caused to bfe 

 exhibited in the circus, an elephant, a rhinoceros, 

 a tiger, and a hippotigris. This circumstance ap- 

 pears to us another indication of what we have 

 shown in the history of Canidae ; we mean a certain 

 and gradual diffusion of species over parts of the 

 world where previously they did not exist, for the 

 Romans, though possessed of less influence in Equa- 

 torial Africa than the Egyptians during the ages 

 when Meroe flourished, nevertheless obtained a spe- 

 cimen of the Zebra, while no such animal appears 

 painted in any known monument of earlier date in 

 thft valley of the Nile that has yet been discovered. 

 The indication of Hippotigris is so apposite, that 

 almost all travellers have made a similar comparison 

 on observing any one of this group of animals, and 

 on this account we have thought it the most befitting 

 appellation for the group collectively taken. If the 

 ancients were silent concerning the striped species, 

 no wonder that the moderns were not better informed 

 until the Portuguese established themselves on the 

 coast of Congo and Angola ; here they encountered 

 the Zebra, which seems to be the Negro mutation of 

 the Abyssinian Zeuru of Lobo and the Galla Zeora, 

 or Zecora, according to Ludolphus ; neither, how- 

 ever, of these indicated species is the Zebra of the 

 moderns, for the earliest descriptions, such as that 

 of Pigafetta, applies to a Dauw, or a species with 

 alternate stripes of black and brown upon a lighter 

 general surface, which we shall describe more parti- 

 cularly 



