1907.] MONKEYS OF THE GENUS CERCOriTHECUS. 681 



Atiahjtical Key to the Groups of Species. 



a. Prevailing colour nearly l)rick-red ; limbs Lelow elbow and knee wlute in 



adult ; skin of face and of ears pale tlesh-colonred. PATAS-group (p. 74.'2). 

 a'. Colour not brick-red ; limbs below elbow and knee not wliite ; face 

 and ears never whollj' pallid. 

 h. Long snow-'A'liite uprunning whiskers associated witb a blackish or 

 dark red bell^'. 

 c. A white brow-band; markedly white chest and inside of fore limbs; 

 a tuft of hair on the chin and a white stripe on outside of thigh. 



DiANA-group (p. 682). 



c'. No white brow-band ; chest not wholly white and inside of fore limbs 

 not white ; no tuft on chin and no stripe on thigh. 

 d. Belly blackish and the same colour as the limbs; top of head 



blackish, finely speckled, not encircled ... L'HOESii-group (p. 714-)- 

 d'. Belly and chest red, ditt'ering from the limbs in colour; top of 

 head encircled with black and mostly golden green. 



EEXTlIKOGASTEE-group (p. 715). 



h'. Whislcers variously coloured, when white and uprunning associated 

 with a white or whitish under side. 

 e. A white cordate nasal spot accompanied by a wliite or greyish-white 

 under side and in.side of limbs ; under side of tail white and strongly 

 contrasted in tint with the upper side, at least proximally. 



PETAUEISTA-grOUp (p. 717). 



e'. Nasal spot, when present and subcordate not accompanied by white 



on the under side of the body and tail and inside of the limbs. 



/. A very distinct patch of yellow or greyish-yellow hair on the cheek 



defined by a black stripe above and below. CEPHUs-group (p. 721). 



f. On the cheek no distinct patch of yellow hair defined above and 



below by a black stripe rising respectively from the brow and 



upper lip. 



g. Upper and lower lips pink and contrasted with the slate-blue 



hue of the rest of the face ; white, yellow, or red colour of the 



under side sharply contrasted, especially on the fore limbs, 



with the black or speckled upper and external areas ; (arms 



almost always black) MoKA-group (p. 708). 



fl'. Face not so coloured ; colour of underside and of inner side of 

 limbs not so .sharply contrasted. 

 //. External surface of arms black or darker than back ; under 

 side dusky or black. 

 i. Summit of head with large red brow-band followed by a 

 jet-black transverse stripe ; a white beard, whitish thigh- 

 stripe; two inches at base of tail sharply contrasted with 



the rest, which is black NEGLECTUS-group (p. Q^A). 



i'. Summit of head not so coloured ; no white beard or thigh- 

 stripe; no sharp contrast in colour at base of tail. 

 j. A very conspicuous white patch on the nose. 



NiCTiTAXS-group (p. 695). 



f. No conspicuous or isolated white nose-spot. 



k. Black prevailing on head, nape, shoulder, belly, and 

 thighs ; when the head is strongly speckled the belly 

 and thighs are black, when the belly and thighs are 

 speckled the head is black, except for the brow-band ; 



(belly rarely red) LEUCAMPYX-group (p. 687). 



Tc'. Black absent or at least not dominant on the above- 

 mentioned areas ; back usually reddish or yellowish. 



AiBOGULARis-group (p. 699). 

 //. External surface of arms not black, sometimes the same 

 colour as the body, usually rather paler and greyer. 

 1. Face almost alwa3S black, rarely mottled or freckled with 

 pigment; whiskers usually growing upwards and back- 

 wards over the ear ^THiopS-group (p. 725). 



I' . Face particoloured, pallid, with black nose and lips. 



TALAPOiN-group (p. 740). 



