THUMB LESS MONKEYS. 91 



most distinctive characteristic of the species is the silveiy-wliite of the thighs, from 

 which it derives its name. The haunches are, moreover, generally grev. The 

 white hair of the thighs is shorter than that on the bodj^ 



The Bay Colob {Colohus ferrugineus). 



Very different in coloration from any of tlie species yet mentioned is the bay 

 colob, definitely known from the Gambia and the Gold Coast, and of which a 

 single specimen was brought alive to England in the autumn of 1890, but, 

 unfortunatel}-, did not long survive its arrival. 



This handsome species lias comjiaratively short hair, which, on the crown of 

 the head and the back and upper part of the sides is blackish-grej-, while the 

 cheeks and throat, as well as the under parts and tlie limbs, ai-e of a rich 

 fermginous bay. The upper part of the root of the tail is blackish, but the 

 remainder of a reddish-ljrown. The ears and tiie greater part of the face are bluish, 

 but the nose and lips are flesh-coloured. Altogether the bay colob is a striking 

 species, which, once seen, will always be easily recognised. 



The Crested Colob {Colohus cristatus). 



The last of the thumbless monkeys we shall mention is the crested colob, 

 which is likewase a West African species. It is readily distinguished by its short 

 yellowish-brown fur, which becomes grej'er on the front of the body; the 

 shoulders and outer sides of the arms, the thi-oat, chest, under parts, and inner sides 

 of the limbs being greyish-white. It differs from all the other species in that the 

 hair on the forehea<l railiates from two points on the temples, and that there is a 

 low erect crest of longer hairs running along the middle line of the head. 



