338 MR. C. BODEN KLOSS ON 
far the most striking of the forms into which the species has been 
divided. 
The darkest and most concolorous animals occur about the 
latitudes of Penang and Kedah, and the races become more variega- 
ted as they recede from that locality both to the north and south- 
wards ; but animals from the latter region do not attain the contras- 
ting colours which are so marked in the present subspecies. The 
description of the typical form applies perfectly to examples from 
the extreme south, and Cantor's statement regarding its habitat, 
“district adjacent to Singapore, Malayan Peninsula” (Journ, Asiat. 
Soc. Bengal, xv, 1846, p. 174) may be taken as indicating the 
typical locality. 
In colour these two females agree perfectly with the male 
which is the type of the sabspecies,! except that in one of them the 
median area of the upptr back is paler; their skulls are smaller and 
have considerably smaller rostrums. 
Mr. K. G. Gairdner has found P. obsewra ( identified im itt, as 
the present race ) generally distributed in the province of Petcha- 
buri, but states that it is not found in Siam north of Lat. 13° 20°. 
Gyldenstolpe (Kungl. Sv. Vet. Akad. Handl, 57, No. 2 p. 5. 
1916) records P. 0. jlavicauda (Elliot) from Koh Lak and P. o. 
haloniger (Cantor) from Koh Lak Paa (Koh Lak forest), which is 
within a day’s walk of the former place. Apart from the improba- 
bility of finding two such geographical races in the same district, 
halonifer is the name given to a local form from Penang Id., and that 
identification, at least, is not likely to be correct. The present 
females and the type have been compared with series of both those 
forms and all three races differ considerably. 
Méasurements :—See table posteu. 
2. Presbytis argenteus, nov. 
Presbytis phayre’, Gairdner, Journ. Nat. Hist. Soc. Siam, 1, p. 252 
(1915). 
'ypes. Adult male and female (skins and skulls), Nos. 2144 
1 By an error in the original description the type was stated to be 
a female. 
JOURN. NAT. HIST, SOC. SIAM. 
