Source : Webster's Revised Unabridged Dictionary (1913)

Trematodea \Trem`a*to"de*a\, n. pl. [NL., from Gr. ? having
   holes, from ?, ?, a hole.] (Zo["o]l.)
   An extensive order of parasitic worms. They are found in the
   internal cavities of animals belonging to all classes. Many
   species are found, also, on the gills and skin of fishes. A
   few species are parasitic on man, and some, of which the
   fluke is the most important, are injurious parasites of
   domestic animals. The trematodes usually have a flattened
   body covered with a chitinous skin, and are furnished with
   two or more suckers for adhesion. Most of the species are
   hermaphrodite. Called also {Trematoda}, and {Trematoidea}.
   See {Fluke}, {Tristoma}, and {Cercaria}.

Source : WordNet®

Trematoda
     n : parasitic flatworms (including flukes) [syn: {class
         Trematoda}]