RHINOCEROS LEPTORHINUS. 369 



nasal horn. We may therefore infer, from the latter 

 character, that the second horn was smaller in the 

 leptorhine than in the tichorhine Rhinoceros, and con- 

 nect in physiological relationship with this indication 

 the non-extension of the bony supporting wall beneath 

 the second platform.* Another distinction is the nar- 

 rower interspace between the curved ridges (t t) which 

 indicate the extent of origin of the temporal muscles 

 upon the sides of the cranium : and this is not due 

 to any difference of age ; for the skull of the ticho- 

 rhine Rhinoceros, with which I compared the Clacton 

 specimen, belonged to an old individual, and yet 

 exhibited the same superior width between the tem- 

 poral ridges as is shown in the Cuvierian figure above 

 referred to. The plane of the occiput is less inclined 

 from below upwards and backwards than in the Rh. 

 tichorhinus, and this region of the skull of the lepto- 

 rhine species differs more strik- 

 ingly in its form (fig. 140) : it is Fig. 140. 

 narrower in proportion to the 

 length of the skull, and especially 

 at the upper part, which gives it 

 a triangular figure with the apex ] 

 cut off. In the Rh. tichorhinus \ 

 it is more square-shaped, and the 

 upper overhanging ridge is thicker 



and more rugged, indicating more Occiput of Rhinoceros lepto- 

 , , . , r/timis. i nat. size. Clacton. 



powerful ligamentous and muscu- 



* The existing species of two-horned Rhinoceroses of Africa present the same 

 difference in the proportions of their horns, as was manifested by the two extinct 

 European species above compared. The Rh. Keitloa of Dr. Smith has both horns 

 of equal length ; the Rh. simus has the frontal horn much shorter than the 

 nasal one. 



2 B 



