Body Wall 5. Respiratory System 8. In Summary: Phylum Platyhelminthes. The Platyhelminthes, both parasitic and free-living taxa, share a set of characters: they are nonsegmented acolomates without an anus, which lack respiratory and circulatory systems but possess an excretory system. Platyhelminthes are triploblastic, bilaterally symmetrical, dorsoventrally flattened, acoelomate flatworms with organ grade of construction without a definite anus, circulatory, skeletal or respiratory system but with Protonephridial excretory system and mesenchyme filling the space between the various organ of the body.. This digestive system is incomplete in most species. Reproductive System 10. https://biorespitorysiteproject.weebly.com/platyhelminthes.html Unique Characteristics of Platyhelminthes. The phylum platyhelminthes consists of some of the msot simple organisms in existence. Their shape allows oxygen and nutrients to … ... and nervous system, but no respiratory system. Organs of Adhesion 4. Development 11. The oxygen that enters and the carbon dioxide that leaves the body diffuses through the body wall. Most are bilaterian, unsegmented, soft-bodied invertebrates. Flatworms are acoelomate, triploblastic animals. FLATWORMS Kingdom Animalia Phylum Platyhelminthes Ex. Structure of Platyhelminthes 3. Nervous System 9. Excretion: The waste excreted by the cells is picked up by the blood and carried back into the digestive system for elimination through the alimentary tract. They lack circulatory and respiratory systems, and have a rudimentary excretory system. Some of the characteristics that distinguish the organisms belonging to phylum Platyhelminthes from others are: Presence of flame cells. This phylum is composed of 12,00 species; ... Bedford's Flatworm lacks any definite respiratory organs. Excretory System 7. This means that the flatworm's body is shaped so that oxygen can enter and carbon dioxide can leave through all parts of the body by simple diffusion. Members of this phylum are soft, thin-bodied, leaf or ribbonlike worms, including the familiar planaria of ponds and streams, as well as the flukes and tapeworms parasitic in human and other animal bodies. Phylum platyhelminthes 1. Figure: Phylum Platyhelminthes. PLATYHELMINTHES. They have no respiratory or circulatory organs. Ladder-like nervous system. https://ineedrespirationasap.weebly.com/platyhelminthes.html Phylogenetic Considerations. Digestive System 6. In addition, all are hermaphroditic and asexual (mainly paratomy) and sexual reproduction are present. Habit and Habitat of Platyhelminthes: The platyhelminthes are mostly ecto or endoparasitic and few are free-living. Platyhelminthes The phylum name Platyhelminthes literally means "flatworms." The nervous system comprises the brain and two longitudinal nerve cords arranged in a ladder-like fashion. For this reason, they are flat. Circulation: Platyhelminthes have no actual circulatory system.