444 



PROF. W. H. FLOWER ON THE CRANIAL AND [May 16, 



distinct types, and no more, these three exactly coinciding with 

 those described by Cuvier. Whether more species exist of which 

 we have as yet received no specimens, or whether any of these 

 types, as I have called them, represent several species separated by 

 characters, external or anatomical, not available at present, I cannot 

 say, especially in the prevailing uncertainty of the use of the word 

 " species." I only mean to imply that there is nothing that I can 

 distinguish in the materials at hand to justify their further separa- 

 tion. 



These three are (arranged according to size) : — 1. R. unicornis, 

 Linn., = R. indicus, Cuv. (R. A. 1817); 2. R. sondaicus, Cuv. (in 

 Desmarest, Mamm. 1822), = R. javanicus, F. Cuv. & Geoff. 

 (Mamm., 1824); 3. R. sumatrensis, Cuv. (R. A. 1817). The 

 skulls of these three species can be distinguished from one another 

 at a glance, at any age. 



Leaving out numerous minor characters, for which I must refer to 



Fig. I. 



Side view of posterior part of skull of Bhinoceros sumatrensis. One fourth 

 natural size. 



m, External auditory meatus ; pg, postglenoid process of the squamosal ; pt, 

 posttympanic process of the squamosal ; po, paroccipital process of the 

 exoccipital. 

 [All the figures are from specimens in the Museum of the Royal College of 

 Surgeons.] 



the works previously mentioned, the skull of the last (R. sumatrensis) 

 is separated from either of the others by a most readily recognized 

 peculiarity in the structure of the squamosal bone, which I believe has 

 not been generally observed. I should, perhaps, rather say that the 

 peculiarity exists in the former two species, and that R. sumatrensis 



