6 ERYTHROCEBUS 



occur. At Lake Chad, Nigeria, E. sannio is met with, the only species 

 yet discovered in that large Province, and in Cameroon, E. langeldi 

 was obtained. The locality of one species E. circumcinctus is quite 

 unknown, nor is there any specimen extant, a figure given by Reichen- 

 bach being the only evidence we have of its existence. 



KEY TO THE SPECIES. 



A. Brow band black. 



0. Shoulders not black. 

 a.' Thighs not black. 



a." Nose black E. patas. 



b." Nose white. 



a.'" Rump and tail above ochra- 



ceous E. pyrrhonotus. 



b.'" Rump vinaceous rvifous, grad- 

 ing into bay on tail E. formosus. 



b. Shoulders mostly black. 



a.' Thighs mostly reddish. 

 a." Chin white. 



a.'" Outer side of forearm to hand 



grizzled black and white E. poliophcsus. 



b.'" Outer side of forearm to hand 

 white. 



a."" Nose white ....£. whitei. 



b."" Nose black. 



0.5 Chin white E. kerstingi. 



b.^ Chin black : E. zechi. 



c." Outer side of forearm to hand 



buff E. langeldi. 



b.' Thighs mostly all white. 



a." General color rich bay E. albigenis. 



b." General color speckled orange buff, 



and white E. sannio. 



B. Brow band white E. circumcinctus. 



C. No brow band E. baumstarki. 



Erytheocebus patas (Schreber). 



Simia patas Schreb., Saugth., I, 1775, p. 98, pi. XVI; Bodd., 



Elench. Anim., 1784, p. 59. 

 Cercopithecus patas Erxl., Syst. Regn. Anim., 1777, p. 34; Less., 



