TrematodaIn Cuvier's system of classification, the second family of parenchymatous entozoa, containing the flukes proper, the hectocotyls of cephalopods, and the planarian larvæ of turbellarians. See cuts under Cercaria, Bucephalus, and water-vascular.
TrematodaAn extensive order of parasitic and chiefly entoparasitic worms, which may be found inside the bodies of almost any animal, and sometimes on the gills or skin of fishes; the flukes or fluke-worms. They mostly have a flattened and more or less chitinized body, and a pair or more of suckers for adhering to the tissues of the host. Most trematoids are hermaphrodite or monœcious, but some are diœcious, and all undergo a series of transformations comparable to those of tapes. The well-known liver-fluke of man, Distoma hepaticum, is a characteristic example. (See cercaria, Distoma, fluke, hydatid, redia, and sporocyst.) When the order is raised to the rank of a class, as is done by some, the monogeneous and digeneous suborders become subclasses, and the current families are regarded as orders, as Tristoma and Polystoma of the former division, and of the latter Monostoma, Distoma, Gasterostoma, and Holostoma. Also Trematoidea, Trematodea, and Trematoida.
Chambers's Twentieth Century Dictionary
n.plTrematodatrem-a-tō′da a class of flat-worms whose members are parasitic in or on a great variety of animals, the body unsegmented, leaf-like or more or less cylindrical, and provided with adhesive suckers