The Collaborative International Dictionary of English v.0.48:

Coluber \Col"u*ber\, n. [L., a serpent.] (Zool.)
   A genus of harmless serpents.
   [1913 Webster]

   Note: Linn[ae]us placed in this genus all serpents, whether
         venomous or not, whose scales beneath the tail are
         arranged in pairs; but by modern writers it is greatly
         restricted.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Coluber
    n 1: racers [syn: Coluber, genus Coluber]