Turbellaria
Bedford's Flatworm, Pseudobiceros bedfordi
Scientific classification
Kingdom: Animalia Phylum: Platyhelminthes Class: Turbellaria Ehrenberg, 1831
Orders
(Acoela) Catenulida Haplopharyngida Lecithoepitheliata Macrostomida (Nemertodermata) Polycladida Prolecithophora Rhabdocoela Seriata Temnocephalida Image File history File links Download high resolution version (1024x768, 663 KB) Bedfords Flatworm (Pseudobiceros bedfordi) photographed by Jan Derk in March 2006 in Fihalhohi, Maldives. ... For other uses, see Scientific classification (disambiguation). ... For other uses, see Animal (disambiguation). ... Classes Monogenea Trematoda Cestoda Turbellaria The flatworms (Platyhelminthes, Greek platy: flat; helminth: worm) are a phylum of relatively simple soft-bodied invertebrate animals. ... Christian Gottfried Ehrenberg. ... Families Actinoposthiidae Anaperidae Antigonariidae Antroposthiidae Childiidae Convolutidae Dakuidae Diopisthoporidae Hallangiidae Haploposthiidae Hofsteniidae Isodiametridae Mecynostomidae Nadinidae Otocelididae Paratomellidae Polycanthiidae Proporidae Sagittiferidae Solenofilomorphidae Taurididae Acoela is an order of animals treated either as a group of flatworms or as one of the two classes of the phylum Acoelomorpha, containing the majority of... The Polycladida represents a highly diverse clade of free-living marine turbellarian flatworms. ... The Candy-Cane Worm (Plagiostomum vittatum), a common North-East Atlantic species. ...

Turbellaria are a group of generally small (<1 - 60cm) and free-living members of the flatworm phylum Platyhelminthes. It is nowadays mostly considered obsolete (polyphyletic), and the Acoela and Nemertodermata are excluded from the class into a phylum of their own (Acoelomorpha). Classes Monogenea Trematoda Cestoda Turbellaria The flatworms (Platyhelminthes, Greek platy: flat; helminth: worm) are a phylum of relatively simple soft-bodied invertebrate animals. ... In biology, a taxon is polyphyletic if it is descended from more than one root form (in Greek poly = many and phyletic = racial). ... Families Actinoposthiidae Anaperidae Antigonariidae Antroposthiidae Childiidae Convolutidae Dakuidae Diopisthoporidae Hallangiidae Haploposthiidae Hofsteniidae Isodiametridae Mecynostomidae Nadinidae Otocelididae Paratomellidae Polycanthiidae Proporidae Sagittiferidae Solenofilomorphidae Taurididae Acoela is an order of animals treated either as a group of flatworms or as one of the two classes of the phylum Acoelomorpha, containing the majority of... The Acoelomorpha are a phylum of animals formerly considered flatworms, but now known to be a separate group, basal among the Bilateria. ...

Their locomotion depends on cilia. Most turbellaria are carnivorous, and actively scavenge for food. Most species are marine and freshwater dwellers, but some have evolved to dwell on humid land, as well. Planarians and other flatworms lack organs specialized for gas exchange and circulation. Their flat body places cells close to the water, and the detailed branching of the gastrovascular cavity distributes food throughout the body. Nitrogenous waste, in the form of ammonia, diffuses directly from the cells into its surroundings. Flatworms also have a simple excretory apparatus that functions in maintaining an osmotic balance between the flatworm and the surrounding water. This system is composed of ciliated cells ("flame cells") that waft fluid through branched ducts open to the outside. This allows them to invade freshwater and moist terrestrial environments. cross-section of two cilia, showing 9+2 structure A cilium (plural cilia) is a fine projection from a eukaryotic cell that constantly beats in one direction. ... This tigers sharp teeth and strong jaws are the classical physical traits expected from carnivorous mammalian predators A carnivore (IPA: ), meaning meat eater (Latin carne meaning flesh and vorare meaning to devour), is an animal that eats a diet consisting mainly of meat, whether it comes from live animals...

The planarian Dugesia is a common representative of class Turbellaria. Planariam (family Planariidae) are common freshwater, non-parasitic flatworms of the phylum Platyhelminthes, class Turbellaria. ...

Summary of features for Class Turbellaria (L. turbellae = a combination, aria = like):

• no mitosis in somatic cells; new cells made by totipotent stem cells

• free-living (non-parasitic) or symbiotic flatworms

• dorsoventrally flattened triploblasts with a blind gut

• well-defined nervous system with sense organs (ocelli and ciliary chemoreceptors)

• ganglia concentrated into a brain at one end of the body (cephalization)

• a simple life cycle

• live mostly in marine environments, such as unpolluted ponds or streams

• monoecious (simultaneous hermaphrodites)