KINGDOM ANIMALIA Phylum Platyhelminthes

Phylum Platyhelminthes Members of the four classes of the phylum are known as the “flatworms.”

Members of the Phylum Platyhelminthes …are bilaterally symmetrical. …are acoelomates with only one internal space. …have an organ-system level of organization …are hemaphroditic. …range in size from 1-2 mm to several meters.

Four Important Platyhelminthes Classes 1. Class Turbellaria Mostly free-living flatworms Either carnivores or scavengers Example: Dugesia

Four Important Platyhelminthes Classes 2. Class Monogenea Typically found as parasites on fish Single generation in life cycles Example: Gyrodactylus

Four Important Platyhelminthes Classes 3. Class Trematoda All parasitic flukes Most are internal parasites of vertebrates with complex life cycles Example: Schistosoma

Four Important Platyhelminthes Classes 4. Class Cestoda Most are internal parasites living in the gastrointestinal tracts of vertebrates No digestive system Tapeworms-“the ultimate parasites”