Dr. J. E. Gray on the Dentition of Rhinoceroses. 361 



we get together more specimens and their skulls from different 

 parts of Asia, Jt may turn out tliat more than one species of 

 two-horned llhinoceros inhabit Tenasserim. There is a one- 

 horned one, R.javanicaHj also found there. The photograph 

 of the oldest skull (t. iii. f. 1) and the youngest (t. iii. f. 3) 

 agree in many particulars with our skulls of C. sumatranus 

 from Sumatra — that is to say, in the width of the skull at the 

 lateral condyles and in the narrowness of the space that sepa- 

 rates the temporal muscles of the adult ; but the surface of the 

 lower jaw of the adult specimen most resembles that of C. niger. 

 The latter fact may depend solely upon the age of the specimen. 

 Mr. Blytli informs me that he believes the adult skull (t. iii. 

 f. 1) is the skull of R. Crossii, which he thinks is R. lasiotisj 

 and lie believes that the two younger skulls (t. iii. f. 2 & 3) 

 belong to the black Rhinoceros. The youngest skull (t. iii. 

 f. 3) has the skin of the head and horns attached to it in the 

 Museum at Calcutta. . But the lower jaw in the two younger 

 specimens does not agree in form with the lower jaw of 

 C. niger ; and therefore I should provisionally name them C. 

 Blythii. 



The African Rhinoceroses have the intermaxillary bones 

 small, laminar, situated on the front end of a bony plate sepa- 

 rated by a suture (which becomes obliterated in the older spe- 

 cimens) in the inner side of the front part of the maxillaj ; and 

 it has a tooth on the edge, whicli generally falls out in the adult 

 animal ; hence they are usually described as having no inter- 

 maxillary cutting-teeth. The lower j aw of the young R. hicorn is 

 (1365 h) has a small cylindrical cutting-tooth on each side of the 

 broad end of the jaw, which disappears in the older animals ; 

 and the breadth of the front of the jaw does not increase, and 

 therefore becomes smaller compared with the size of the skull. 

 In the skull of the foetal specimen of R. hicornis^ 8| in. long 

 (1365 A), with the three grinders but partially developed, the 

 interraaxillaries are cartilaginous, and show rudiments or, 

 rather, nuclei of two teeth. 



The lamina on the inside of the maxilloB of these African 

 Rhinoceroses, bearing the intermaxillaries, is represented in the 

 Asiatic Rhinoceroses by a broad portion of the inside of the 

 maxillas, which is marked by an external groove; but in these 

 animals the broad intermaxilla is attached to the end of the 

 maxilla, as well as to the end of this defined part. 



EXPLANATION OF PLATE XL 



The skull of the two-horned Rhinoceros (Ceratorhimis niger) from 

 Malacca ; and a view of its occipital extremity, showing the foiin 

 and breadth of the hinder part of the head. 



