THICK-SKINNED BEASTS. 49 



while in the two skulls of R. sumatranus it is smaller, cii'cular, and 

 some distance from the margin of the apertm-e. The fi'ont edge of the 

 intermaxillary bones is broader, rounded, and not compressed nor nearly 

 so much produced as the front edge of the intermaxillary bone of the 

 adult skull of B. sumatranus, nor so much as in the skull of the 

 young animal of the same species, which is shorter and broader than 

 in the adult. The giinders of the upper jaw are six in munber, and 

 appear broader than those of the adult B. sumatranus, but they occupy 

 the same length. 



The skull of the Malaccan rhinoceros is not so high behind as that 

 of the adult Sumatran rhinoceros ; and the space in the crown between 

 the temporal muscles is flat, and much wider than that of the adult 

 but not so aged Sumatran rhinoceros in the British Museum. The 

 back end of the upper part of the occiput is not nearly so broad as that 

 of the Sumatran rhinoceros. 



The most striking difference is in the lower jaw. The condyles are 

 further apart ; indeed the whole jaw is wider ; but the outer edge of 

 the hinder angle is much more expanded. This latter pecuHarity, as 

 well as the form of the crown of the grinders in the upper jaw, may 

 arise from the greater age of the specimen. The greatest pecuharity 

 is that the front of the lower jaw is comparatively thin, expanded, and 

 having neither teeth nor alveoh, nor, indeed, one may say, sufficient 

 thickness to hold the large cutting-teeth usually found in the front of 

 the lower jaw of this genus. The grinders are six on each side ; that 

 is to say, the front tooth on each side is retained, whereas it is shed 

 from the skull of the adult but much less aged animal of B. sumatranus 

 in the British Museum ; and the giinders appear to differ in the form 

 of their folds from those of the Sumatran species. 



niger. sumatranus. 



in. in. 



Length from tip of nose to occipital condyle of adult .... 21^ 23 



From front of intermaxillary to occipital condyle 20J 21 



From front edge to back edge of lower jaw 16 J 17 



Width at zygomatic arch 12 11 



Width of hinder end of lower jaw lOg 9^ 



Width of upper part of lower jaw at end of tooth-Hne .... 7^ 6f 



Height of back of skull 13 13^ 



It is very probable that the want of front teeth in the lower jaw 

 may be an individual pecuharity produced by the age of the specimen ; 

 at least I do not think it safe to regard that pecuharity as specific without 

 an examination of more specimens. The toothless front of the lower 

 jaw is like that of the adult Ceratotlieriurn simus, from S. Africa. 



In the 'Annals and Magazine of Natural History,' 1872, x. p. 209, 

 I refeiTed to B. Crossii and thought it might be the same as B. suma- 

 tranus from Tavoy and Tenasserim, mentioned by Blyth, JomTi. 

 Asiat. Soc. Bengal, 1862, p. 156, who figiu*es the skull and horns, and 

 who identifies his animal with my B. Crossii (which was described 

 from a pair of horns, P. Z. S. 1854), and has just informed me that it 

 is the head of the small black rhinoceros with two horns. 



Probably he is correct in thinking that the horn I figured as i?. 

 Crossw belongs to the same species as the skulls which he received from 

 Tenasserim ; but it is to be observed that I have never seen a skull of 



S 



