XVII MANGABEYS AND GUENONS 565 
Macaques and Cercopithecus, giving to them the greenish hue 
which characterises so many of the last two genera. There are 
no laryngeal air sacs as in the Macaques. There are not more 
than seven species. 
The genus Cercopithecus (the Guenons) represents in Africa 
the Oriental and Palaearctic Macaques; the genus has a long 
tail. The cheek pouches are larger than in the genus MJacacus. 
The ischial callosities are less extensive than in that genus. A 
tooth character also distinguishes this genus from J/acacus ; the 
last molar of the lower jaw has, as a very general rule, only 
four cusps instead of the five which are found in JJacacus. The 
supraciliary ridges in the skull are by no means so marked as in 
the allied genera. 
One species, the Talapoin, C. talapoin, has been separated into 
a distinct genus, Jiopithecus, on account of the fact that the 
lower molars have only three tubercles instead of the usual four. 
But if this be done, then Cercopithecus moloneyi, which has a 
lower molar with five tubercles, should also be separated. 
The genus Cercopithecus is limited to Africa, and its numerous 
Fic, 269.—Diana Monkey. Cercopithecus diana. x %. 
species have often a very limited range. They are frequently 
rather brightly coloured, with blue and white patches on the face. 
The Diana Monkey has a pointed white beard. Of the Vervet 
Monkey (C. /alandii) a curious fact was noticed at the Zoological 
