The Collaborative International Dictionary of English v.0.48:

Operculate \O*per"cu*late\, Operculated \O*per"cu*la`ted\, a.
   [L. operculatus, p. p. of operculare to furnish with a lid,
   fr. operculum lid.]
   1. (Bot.) Closed by a lid or cover, as the capsules of the
      mosses.
      [1913 Webster]

   2. (Zool.) Having an operculum, or an apparatus for
      protecting the gills; -- said of shells and of fishes.
      [1913 Webster]

WordNet (r) 3.0 (2006):

operculated
    adj 1: having an operculum [syn: operculate, operculated]