44 



SKETCH OF THE HISTORY OF MAMMALIA. 



The skull of this species differs from that of the two- 

 horned African rhinoceros, not only in the presence of 

 the osseous nasal partition, but in general form and pro- 

 portions. The length and narrowness of the skull are 

 very remarkable, as is also the space between the orbits, 

 which is much more contracted than in the common two- 

 horned species, and the nasal bones are far more elon- 

 gated. In the two-horned rhinoceros the disc which 

 bears the anterior horn is a semi-sphere, in this an oblong 

 ellipse, and a disc of similar figure supports the second 

 horn, whence it may be safely concluded that the horns 



Skull of Fossil Rliinoccros. 



of this fossil species were strongly compressed at the 

 sides. The occipital ridge is elevated and drawn out 

 backwards, so that from the highest point the occipital 

 bone slopes at a very acute angle inwards to the con- 

 dyles. 



About nine fossil species of rhinoceros are described. 



