THE GRYSBACK, &C. 223 



figuration, in the animals belonging to it possessing 

 four horns. It has been named as a subgenus Tetra- 

 cerus. It appears that there is a possibility of two 

 species with four horns existing, in the one perfectly 

 smooth, in the other, rugged at the base ; the mate- 

 rials, however, for establishing the latter, are imper- 

 fect ; and, at present, we shall confine ourselves to 

 that first described by General Hardwicke. 



