298 



See page 302. 



THE ASININE GROUP. 



Although there are no A^ery prominent external 

 differences, the eye of the most superficial observer 

 is almost always sufficient to distinguish this se- 

 condary and less elegant form of Equidae from the 

 Caballine species already described. We have al- 

 ready remarked on the conflicting opinions of natu- 

 ralists, whether the two forms should be separated 

 by generic names; and though we adopt the ar- 

 rangement of Mr. Gray, it is because it is viewed 

 by us as more advantageous in a natural system of 

 classification to refer the species of minor groups to 

 their common centres, than to insist on the necessity 



