Knowra Flatworm Flatworm A flatworm is an invertebrate in the phylum Platyhelminthes, with a soft, flattened body and usually no body cavity. The phylum includes free-living species and parasites.
Platyhelminthes : A phylum of bilaterian animals that includes flatworms, from free-living planarians to parasitic tapeworms. The phylum name identifies the taxonomic group containing every flatworm.
Ciliary gliding : A form of locomotion in which cilia move an animal across a surface, often over secreted mucus. Many free-living flatworms glide using cilia on their ventral surfaces.
Schistosomiasis : A parasitic disease caused by blood flukes of the genus Schistosoma. This major human disease is caused by parasitic flatworms with freshwater snail hosts.
Nematode : A roundworm in the phylum Nematoda, typically cylindrical and equipped with a complete digestive tract. Nematodes contrast with flatworms in body shape and possession of a through-gut.
Acoelomate : An animal whose body lacks a fluid-filled cavity between the digestive tract and outer body wall. Flatworms are classically described as acoelomates, with tissues filling the space between body surfaces.
Flame cell : A ciliated terminal cell in a protonephridium that drives fluid through excretory tubules. Its beating cilia help propel excess water through the flatworm's excretory system.
Taeniasis : An intestinal infection caused by adult tapeworms of the genus Taenia. Tapeworms are flatworms whose adult stages can live in the human intestine.
Annelid : A segmented worm in the phylum Annelida, including earthworms, leeches, and bristle worms. Annelids have segmented bodies and a coelom, unlike the unsegmented, acoelomate flatworm plan.
Bilateral symmetry : A body plan with left and right sides that are mirror images across one plane. Flatworms share this body plan, which is associated with directed movement and a distinct head end.
Regeneration (biology) : The regrowth or replacement of lost or damaged body parts in an organism. Some flatworms can rebuild an entire body from a small fragment after injury.
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