Mollusca Porifera Cnidaria Platyhelminthes Nematoda Annelida Arthropoda Echinodermata Chordata Review Questions Planarian   Planarian  is the common name given to many non-parasitic flatworms of  Turbellaria   class . Planaria are common to many parts of the world, living in both saltwater and  freshwater . Some species are  terrestrial  and are found under logs,