The Collaborative International Dictionary of English v.0.48:

Lemur \Le"mur\ (l[=e]"m[u^]r), n. [L., a ghost, specter. So
   called on account of its habit of going abroad by night.]
   (Zool.)
   One of a family (Lemurid[ae]) of nocturnal mammals allied
   to the monkeys, but of small size, and having a sharp and
   foxlike muzzle, and large eyes. They feed upon birds,
   insects, and fruit, and are mostly natives of Madagascar and
   the neighboring islands, one genus (Galago) occurring in
   Africa. The slow lemur or kukang of the East Indies is
   Nycticebus tardigradus. See Galago, Indris, and
   Colugo.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lemur
    n 1: large-eyed arboreal prosimian having foxy faces and long
         furry tails