Platyhelminthes
-The flatworms, flat worms, Platyhelminthes, Plathelminthes, or platyhelminths are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates
-Over half of all known flatworm species are parasitic and some do enormous harm to humans and their livestock.
-The vast majority of turbellarians are hermaphrodites (have both female and male reproductive cells), and fertilize eggs internally.
Structures and Functions
they have moderate cephalization, ganglia (groups of nerve cells), and flame cells (cells that help keep osmotic pressure)
Classes
Turbellarians - non parasitic
Flukes - all parasitic
tapeworms - all parasitic