1908.] NEW CERCOPITHECUS MONKEY. 159 



conspicuous rusty-bvown brow-band like that of G. neglect as, 

 but melting posteriorly into the general coloui- of the rest of the 

 head, and not sharply defined by a jet-black band. The area in 

 front of the ears slightly tinged with rufous-brown, but the i-est of 

 the head, the cheeks, neck, and dorsal and lateral surfaces of the 

 body closely speckled greyish -yellow and black. The outer surface 

 of the thighs and of the upper arms also similarly speckled, but, like 

 the cheeks, rather more rufous than the body. On the shoulder and 

 upper arm there is a lighter stripe such as is seen in G. neglectits, and 

 there is a corresponding stripe on the outer side of the thigh, but 

 this is not nearly so conspicuous as the thigh-stripe of G. iieglectas, 

 being of a dirty yellow and not white. The lower arms are dark 

 brown and finely speckled exbernally, but not jet-black as in 

 G. neglectus, whitish stained marginally with yellow on the inside. 

 Hands and feet somewhat rubbed, scantily clothed with wdiite 

 hair. Tail not black, but covered with speckled hairs, resembling 

 in tint those of the body, rufous at base. Hairs on the thi-oat 

 white, but not forming so long a beard as in G. neglectus. Chest 

 and belly greyish with a decidedly rusty tinge. Belly and inside 

 of the thighs white, but the hairs beneath the callosities and on 

 the backs of the thighs not white but tinged distally with rusty 

 red. 



Loc. Unknown, probably Upper Congo. 

 ■ This species is evidently related to G. neglectus, as is testified by 

 the red-brown band, the whiteness of the lips and chin, and the 

 presence of the pale stripe on the thigh, not to mention the 

 corresponding stripe on the uppei- pai-t of the arm and the 

 general colour of both the upper and the under side. It might 

 almost be briefly diagnosed as a species of GercojnthecUjS differing 

 from G. neglectus in lacking the bhick areas characteiistic of the 

 latter. The two may be contrasted as follows : — 



a. The i-ed area of the forehead sharply defined postei-ioi'ly by 

 a jet-black band ci'ossingthe summit of the head froni side 

 to side ; hairs beneath the callosities white ; tail, with the 

 exception of a couple of inches at its base, jet-black. 



neglectus. 



a'. The red area on the forehead not sharply defined behind, but 

 blending with the speckled tint of the top of the head, 

 which has no black transverse band ; liaii-s beneath the 

 callosities not white but tinged with rusty yellow ; tail not 

 black, but the same colour as the back ezrce. 



Up to the present time G. neglectus has occupied in the genus 

 an isolated position, and opinions as to its aflinities have differed. 

 By Drs. Sclater, Forbes, and Trouessart it was associated with 

 G. (liana on account of the presence of a beard of longish haii'S on 

 the throat and chin, and of a white stripe on the outside of the 

 thigh. But in the monograph of the genus Gercopithecus recently 

 published by this Society (P. Z. S. 1907, pp. 677-746), I put 



Pkoc. Zool. Soc— 1908. Xo. XT. 11 



