The Collaborative International Dictionary of English v.0.48:

catamountain \cat"a*moun`tain\, cat-a-mountain
\cat"-a-moun`tain\n.
   1. the bushy-tailed European wildcat (Felis silvestris)
      resembling the domestic tabby and regarded as the ancestor
      of the domestic cat.

   Syn: European wildcat, Felis silvestris.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

catamountain
    n 1: bushy-tailed wildcat of Europe that resembles the domestic
         cat and is regarded as the ancestor of the domestic cat
         [syn: European wildcat, catamountain, Felis
         silvestris]