A class in the phylum Platyhelminthes (the flatworms), consisting of flukes with a leaf-shaped body and two muscular suckers, and an acelomate parenchyma-filled body cavity. Circulatory system and sense organs are not present, but an incomplete alimentary canal is found (lacking an anus). Flukes of interest to human or veterinary medicine are members of the order Digenea, with complete life cycles involving embryonic multiplication in a mollusk as their first intermediate host. The other order, Monogenea, consists chiefly of parasites of fish that have a simpler pattern of direct development on a single host. [G. trematodes, full of holes, fr. trema, a hole, + eidos, appearance]
* * *
Trem·a·to·da .trem-ə-'tōd-ə n pl a class of the phylum Platyhelminthes including the flukes and related parasitic flatworms that usu. have no cellular epidermis or cilia but have a chitinous cuticle covering the body, suckers for adhesion, and a well-developed alimentary canal
* * *
Trem·a·to·da (trem″ə-toґdə) [Gr. trēmatōdēs pierced] the flukes, a class of the phylum Platyhelminthes. Most are parasitic, with animals becoming infected by eating uncooked or undercooked fish, crustaceans, or vegetation. All flukes require a mollusk as their first intermediate host, in which a complex developmental cycle takes place. The larval stage, which escapes from the mollusk, may either enter a second intermediate host (fish, crustacean, or another mollusk), encyst on vegetation, or penetrate directly into the skin of the definitive host. Important trematodes infecting humans belong to the genera Clonorchis, Dicrocoelium, Echinostoma, Fasciola, Fasciolopsis, Gastrodiscoides, Heterophyes, Metagonimus, Opisthorchis, Paragonimus, and Schistosoma.Medical dictionary. 2011.