100 PYGATHRIX 



genera. Gray's characters for the genus are trivial and as Mr. Thomas 

 says are based upon external characters and the relative proportions 

 of fore and hind limbs, in themselves quite insufficient for the estab- 

 lishment of a distinct genus. Mr. Thomas practically abandons these, 

 and relies for the establishment of Pygathrix upon the position of 

 the basal axis of the braincase which is "set on the facial bones at 

 quite a different angle in the two genera being far more strongly 

 inclined in Pygathrix, in which, as a consequence the posterior nares 

 are of enormously greater height." 



In regard to the skulls of P. nem^us and P. nigripes, they vary 

 considerably in shape, and although nigripes is the larger animal, its 

 skull is smaller, has a more depressed braincase, having less height, 

 with a short facial angle. Among the Langurs there is no little 

 cranial variation, and if any single character is deemed sufficient for 

 the establishment of a distinct genus, it would probably be necessary 

 to increase materially such prominent divisions, and which, up to the 

 present have been quite sufficiently segregated under subgeneric terms. 



There is nothing so vitally important in the cranial difference men- 

 tioned by Mr. Thomas as to necessitate a distinct genus for the two 

 species concerned, a difference never referred to by Authors when 

 conferring generic rank on these monkeys, and therefore not considered 

 by them of sufficient importance to be mentioned. The position of the 

 facial bones to the basal axis of the cranium, may possibly be regarded 

 as of sufficient importance to cause the creation of a subgeneric divi- 

 sion, if the known species included in it, at present but two, present 

 the same peculiarity in an equal degree, (which these two species do 

 not), but it can hardly be deemed of such extreme importance as to 

 separate the two Langurs from all the rest of their relatives, (with 

 whom they are closely allied in most respects), by a distinct generic 

 rank. Believing that sufficient reasons have not yet been advanced 

 for this fact to be established, P. nemceus and P. nigripes have been 

 continued in the genus Pygathrix, but tentatively in a subgeneric divi- 

 sion of the same name. Geoffroy, who proposed (1. c.) the genus 

 Pyg.'Vthrix for Simia nemceus gives the facial angle at 50°, the same 

 as his Cercopithecus, which includes also various species of Pyga- 

 thrix, such as P. AURATUS, P. ENTELLUS, CtC. 



Pygathrix nigripes (A. Milne-Edwards). 



Semnopithecus nigripes A. Milne-Edwards, Nouv. Archiv. Mus. 

 Hist. Nat., Paris, VI, 1871, p. 7; Blyth, Journ. Asiat. Soc. 

 Beng., XLIV, 1875, p. 11; Schleg., Mus. Pays-Bas, Simije, 



