100 PYGATARIX 
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. NicRIPEs, they vary 
considerably in shape, and although NicrRiIPEs 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. neme@us and P. nigripes have been 
continued in the genus Pygathrix, but tentatively in a subgeneric divi- 
sion of the same name. Geoffroy, who proposed (lI. c.) the genus 
PyGaTHRIx for Simia neme@us 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, etc. 
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, Simiz, 
