Source : Webster's Revised Unabridged Dictionary (1913)

Mamgabey \Mam"ga*bey\, n. [So called by Buffon from Mangaby, in
   Madagascar, where he erroneously supposed them be native.]
   (Zo["o]l.)
   Any one of several African monkeys of the genus {Cercocebus},
   as the sooty mangabey ({C. fuliginosus}), which is sooty
   black. [Also written {mangaby}.]