The Collaborative International Dictionary of English v.0.48:

Ouistiti \Ouis"ti*ti\, n. [F.] (Zool.)
   See Wistit.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wistit \Wis"tit\, n. [Prob. from native name: cf. F. ouistiti.]
   (Zool.)
   A small South American monkey; a marmoset. [Written also
   wistiti, and ouistiti.]
   [1913 Webster]