MACACUS. 



49 



The skull of the adult specimen in the British Museum, agreeing with Blain- 

 ville's figure of tlie skull of M. arctoides, is distinguished from the others by the 

 great development of its orbital ridges and the depth of its temporal fossa ; the 

 former are of great thickness and are thrown forwards, so that the orbits are con- 

 siderably broader than high. The skull is longer from the frontal to the occipital 

 than in M. melanotus and M. brunneiis. The facial portion is more developed than 

 in these latter in proportion to the more advanced state of its dentition. The base 

 of the skull is also broader and the basicranial axis more anteriorly projected than 

 in M. melanotus or M. brunneus. The zygomatic arch is also of great strength as 

 compared with these skulls. In all these characters it only evinces its greater 

 maturity, and there are no others that present themselves that would indicate any 

 specific distinction between it and these two supposed species ; and these remarks 

 seem to be verified by the table of measurements, when due allowance is made 

 for its greater age. 



The bones of the skull of the adult M. arctoides are unnaturally thick, as 

 are also those of M. brunneus ; and this condition is in all likelihood attributable 

 to confinement; whereas the skull of M. melanotus has no more than the thickness 

 generally characteristic of healthy animals^ although it was also a specimen kept 

 in confinement. 



A comparison of the bones of M. brunneus and of M. arctoides in the British 

 Museum, while it does not reveal any difference in their forms, yet shows them 

 to be notably smaller in the specimen of M. brmmeti-s. But a consideration of the 

 relative ages of the bones as revealed by the conditions of their epiphyses fully 

 accounts for their difference of size. 



The credit is due to Dr. Sclater of being the first to point out that M. melanotus,'^ 

 Ogilby, and the monkey from the Kakhyen hills and Cachar,'' are not different 

 from M. arctoides, Is. Geoff. ; and Dr. Murie* shortly afterwards adopted a similar 



' Epiphyses lost. 



2 Proo. Zool. Soo. 1872, p. 203- 



2 Proc. Zool. Soo. 1860, p. 420. 

 * Ibid, pp. 770, 771. 



a 



