26 SIMIID^. 



deep black. There are no parietal whorls ; but the hair on the head is long and 

 directed backwards, and originates in a peak as far down as the glabella, and is 

 smoothed down on the top of the head from the occipital crest backwards, and is 

 whitish with a yellowish tint. On the back of the neck and between the shoulders 

 the colour tends to ashy brown, and the rest of the body posteriorly is somewhat 

 paler than the sides. The tail is concolorous with the hind part of the back and 

 much longer than the body, but not tufted. The under parts and inside of the 

 limbs and outside of the thighs are of a slightly paler tint than the upper parts. 

 The mouth and eyelids are whitish, but the rest of the face is black. The newly- 

 born young is bright fulvous, but the fur soon changes, and in specimens with the 

 body 11-50 inches in length, the fur is dark ashy brown, very faintly paler on the top 

 of the head, which tends to grey. The hair above the orbits and on the sides of 

 the cheeks is black, which is also the colour of the hands and feet. The rufous 

 colour of the young is most slow to disappear from the head, throat, flanks, thighs, 

 and the terminal half of the tail. Length of the adult male body 1 foot 9 inches, 

 tail 2 feet 8 inches. Although there is a somewhat strong resemblance between the 

 colouring of this species, excluding the pale hairs on the head, and that of S. siamensis 

 which is associated with it in Malacca, as is proved by Cantor's catalogue and speci- 

 mens, yet the S. siamensis {S. albocinereus, Cantor), in the presence of its crest, is 

 more closely allied to ^S'. mitratus, of which it appears to be the continental representa- 

 tive. S. obscurus, on the other hand, presents some general characters which 

 affine it to the somewhat similarly coloured species on the opposite side of the Eay 

 of E en gal, viz., S.johnii. 



The skull of S. obscurus is distinguished from that of S. siamensis by the 

 narrower character of its face, the less outward projection of the external orbital 

 process of the frontal, and by its less capacious orbits. The frontal region also is 

 much narrower than that of S. siamensis, in which the area between the temporal 

 ridges is broad and expanded, whereas it is much more limited in this species. The 

 orbital septum anteriorly is longer and broader tban in iS'. siamensis. It differs 

 also from the skull of true S. maurus, by the greater flattening and expansion of 

 the occipital region and the longer and less obtuse character of the brain-case 

 and the greater breadth of its base. 



This species occurs in Siam and the Malayan peninsula, and is not unfre- 

 quently offered for sale in the Singapore market. I have examined the types of 

 S. obscurus, S. leucomytax, and S, halonifer, all of which in no way differ from one 

 another. 



Cantor has doubtfully referred the Simla maura, Raffles, to this species, and 

 explains the circumstance that Eaffles described the face as black on the supposition 

 that he had never seen S. maura alive; but the typical example in the Indian 

 Museum, London, is a monkey in no way resembling this species and constitutes the 

 type of S. femoralis, Horsfield, a specimen of which from Cantor exists in the 

 same Museum, and is in no way separable from S. sumatranus, Miiller and 

 Schlegel. 



