The Collaborative International Dictionary of English v.0.48:

Ruff \Ruff\, Ruffe \Ruffe\, n. [OE. ruffe.] (Zool.)
   A small freshwater European perch (Acerina vulgaris); --
   called also pope, blacktail, and stone perch, or
   striped perch.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Blacktail \Black"tail`\, n. [Black + tail.]
   1. (Zool.) A fish; the ruff or pope.
      [1913 Webster]

   2. (Zool.) The black-tailed deer (Cervus Columbianus or
      Cariacus Columbianus) of California and Oregon; also,
      the mule deer of the Rocky Mountains. See Mule deer.
      [1913 Webster]

WordNet (r) 3.0 (2006):

blacktail
    n 1: mule deer of western Rocky Mountains [syn: black-tailed
         deer, blacktail deer, blacktail, Odocoileus hemionus
         columbianus]