The Collaborative International Dictionary of English v.0.48:

Ganoine \Ga"no*ine\, n. (Zool.)
   A peculiar bony tissue beneath the enamel of a ganoid scale.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ganoine
    n 1: shiny substance that resemble enamel and is secreted by the
         corium of certain fishes (especially ganoid fishes) and
         composes the outer layer of their scales [syn: ganoin,
         ganoine]