^ AN INVISIBLE MONKEY 



In most English dictionaries the verb " to mimic " has for 

 its synonyms *' to ape, imitate, counterfeit, or mock " ; and 

 it is thus intimately connected with the monkey tribe, whose 

 imitations of human gestures and actions form one of their 

 most prominent characteristic features. Till a few years 

 ago naturalists were, however, totally unacquainted with 

 any instance among these animals of " mimicry " in its 

 scientific sense — that is to say, no case was known where 

 a monkey, for the sake of protection, resembled in form 

 or coloration either some other animal or an inanimate 

 object. During a journey to Mount Kenya and Lake 

 Barengo, in East Africa, Dr. J. W. Gregory, late of the 

 Natural History Museum, discovered that the peculiar type 

 of coloration characterising certain African monkeys is 

 protective in its nature, and that these monkeys, when 

 in their native haunts, are thereby rendered practically 

 invisible. 



The monkeys in question (one of which is represented 

 in the annexed plate) are known to the natives of certain 

 districts of East Africa by the name of "gueieza." They 

 belong to the group of thumbless apes {Cohdus), which 

 are restricted to the African continent, where they take the 

 place of the langurs, or sacred apes, of India and other 

 Oriental countries. From the other thumbless apes the 

 guerezas (or those species to which that name properly 



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