\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}.