254 CERCOCEBUS 



GENUS IV. CERCOCEBUS. THE MANGABEYS. 



i- 2—2 > ^- 1— 1> "• 2— 2> "^- 3— 3~3*' 



CERCOCKBUS E. Geoff., Ann. Mus. Hist. Nat. Paris, XIX, 1812, p. 

 97. Type Cercocebus fuUginosus E. Geoffroy, = Simia 

 cethiops Schreber. 



Semnocebus (nee Less.), Gray, Cat. Monkeys, Lemurs and Fruit- 

 eating Bats, Brit. Mus., 1870, p. 27. 



Lophocebus Palmer, Science, XVII, New Series, 1903, p. 873. 



Body slender; head oval; muzzle of moderate length; limbs long; 

 callosities large ; tail long ; cheek pouches large ; fingers webbed at 

 bottom ; great toe united by a short web to the next one ; second and 

 third toes united for nearly their entire length, and the fourth is united 

 to the third and fifth on either side as far as the middle joints. Pos- 

 terior lower molars have a fifth posterior cusp as in Pithecus. Facial 

 line straight ; premaxillaries not protuberant, on same line as face ; 

 zygomatic arch high above or below alveolar border of molars. 



The Mangabeys constitute a small group of Monkeys that range 

 from the west to the east coast of Africa, from Guinea and the Congo 

 basin to Uganda and the Tana River. These animals form a kind of 

 connecting link between the Macaques of the genus Pithecus and the 

 members of the genus Lasiopyga, through the genus Rhinostigma. 

 They are lighter in body and more slender in form than the Macaques, 

 and have shorter noses, brows less overhanging and larger callosities 

 as a rule than the species of Pithecus, also have longer limbs, and like 

 them have a fifth cusp to the last lower molars. The stomach is simple 

 and the cheek pouches are large, but the laryngeal air sacs are wanting. 



A prominent peculiarity is the webbing of the digits, and each 

 finger and toe is united to the one next to it, but in a different degree, 

 for while the thumb and index finger, and the great toe and its neighbor 

 are united by a very short web, the second and third toes are connected 

 for nearly their entire length. The tail is very long; and the eyelids 

 white ; and the species lack the brilliant colors that are not infrequently 

 witnessed in species of Lasiopyga. They are arboreal in their habits, 

 and dwell in the dense forests that cover the region in which they are 



