CERCOCEBUS 255 



found. One species, however, has been observed to descend to the 

 ground to seek food. 



Some species have a very sombre coat, and their young are black, 

 and the appearance of the animals in their progress from the youthful 

 to the adult pelage has produced considerable confusion among writers 

 when discussing these Monkeys, ending with the recognition of a 

 number of invalid species, and resultant errors. The disposition of 

 the Mangabeys appears to be gentle; their activity is never ceasing, 

 and they are in the habit of "making faces," or grinning at the observer, 

 exhibiting at the same time a liberal display of teeth. The species are 

 easily arranged into two groups, characterized by the presence or 

 absence of a crest on the head. The non-crested species are possessed 

 of brighter colors, or the strong contrasts produced by a distribution 

 of black and white ; while those with crests have a more subdued dress 

 in which grays and browns are conspicuous, but the bright colors, 

 although altogether wanting save in some instances, are more con- 

 spicuous when existing, on the under parts of the body. 



LITERATURE OF THE SPECIES AND SUBSPECIES. 



1775. Schreher, Die S'dugthiere. 



Cercocebus .^thiops is here first described as Simia cethiops 



(nee Linn.). 

 1792. Kerr, Animal Kingdom. Mammalia. 



Cercocebus torquatus first described as Simia cethiops tor- 



quatus. 

 1799. Audebert, Histoire Naturelle des Singes et des Makis. 



Simia cethiops Schreb., and 5". cethiops (nee Linn.), var A. the 



latter afterwards called athiopicus by F. Cuv., 1821 = C. 



^THiops (Schreb.), and C. atys, albino, undeterminable, are 



given in this book. 

 1812. E. Geoffrey St. Hilaire, in Annates du Museum d'Histoire 



Naturelle, Paris. 



Cercocebus iEXHiops Schreb., redescribed as C. fuliginosus ; 



the remaining species under Cercocebus given by this Author, 



belong to other genera. C. atys, albino, possibly C. ^thiops 



(Schreb.), but really undeterminable. 

 1820. Kuhl, Beitrdge zur Zoologie und vergleischenden Anatomie. 



The species of Cercocebus recorded by this Author are placed 



in the genus Cercopithecus, (Lasiopyga), which includes species 



