The Collaborative International Dictionary of English v.0.48:

Vervet \Ver"vet\, n. (Zool.)
   A South African monkey (Cercopithecus pygerythrus syn.
   Cercopithecus Lelandii). The upper parts are grayish green,
   finely specked with black. The cheeks and belly are reddish
   white.
   [1913 Webster]