614 PROF. R. COLLETT ON A [DcC. G, 



to which 8. femoralis and S. obscurus belong, and ajipears to be 

 closely related to S. hosei from North-west Borneo ^ described in 

 1889 by Mr. Thomas. The distribution of the colouring is in several 

 respects identical with that of the latter, but there is a characteristic 

 difference in the colouring of the cheeks, which do not, as in S. hosei, 

 form a connected white area with the white forehead, but the area 

 is broken by a black band from the edge of the mouth to the ear 

 (in the young male and the female) ; in the old male the upper 

 parts of the cheeks are nearly entirely black. The crest likewise 

 does not slope evenly backwards as in S. hosei, but is reversed on 

 the back of the head and runs upwards towards the centre of the 

 crownl 



From S. femoralis, to which especially the old male seems to be 

 nearly related, it is distinguished by the white forehead and the 

 wholly white under surface, both of head, body, and tail. 



Size. — The fully developed male is about 620 miilim. in length (head 

 and body) ; the length of the tail is about 810 miilim. 



The fully developed female is somewhat smaller. The length of 

 the body (head included) is about 600 miilim. The length of the 

 tail varies, but is about 650 miilim. ; in one specimen it was only 

 590 miilim., whilst in another specimen of equal size it was 710 

 miilim. 



The hair-covering of the head. — The greatest height of the longi- 

 tudinal crest on the crown is about 75 miilim. in the old male, while 

 in the female it is shorter, or from 42 to 58 milHm. It juts out 

 from the centre of the forehead at a short distance from the eye- 

 brows. On the front of the head the crest slopes backwards ; but 

 on the hack of the head it is directed forwards, there being a hair 

 spiral behind each ear. The hairs on the crown thus converge and 

 form a high ])oint on the occiput. On the neck the hairs of the 

 crest again slope backwards. On the sides of the forehead the hairs 

 have likewise (especially in the females) a disposition to form a low 

 crest which runs parallel to the central crest ; the hairs here run 

 together to a projecting point, where they meet the spiral behind the 

 ear. There is scarcely any trace of a chin-tuft, as seen in 8. hosei 

 and other species. 



Colouring. — The upper part of the body is of exactly the same 

 shade as in S. hosei, being a uniform grey colour owing to each hair 

 being black and white in turn (without, however, having the rings 

 sharply defined). Ou the sides of the body and the hinder parts of 

 the thighs the grey colouring shows a tendency to form a darker line 

 in the transition to the white, especially in the older specimens. 



The crest on the crown is black ; the occijmt is partly whitish. 

 The forehead is white, and divided in the middle by a black stripe, 

 which joins the crest. The side crest, which extends from behind 

 the side of the eye to the ear, is black and encloses in front (behind 

 the eye) a whitish space. The lower part of the cheeks and the 

 underside of the head are also white, but a black stripe which stretches 

 backwards to a pointed whisker always runs from the upper jaw 

 ' Proc. Zool. Sec. 1889, p. 159, pi. xvi. 



