Metazoa Haeckel 1874 - multicellular animals see Kingdom Animalia Linnaeus, 1758 Phylum Platyhelminthes Gegenbaur, 1859 - flatworms Class Trematoda Rudolphi, 1808 - flukes see Infraclass Trematoda Rudolphi, 1808 Order Digenea Carus, 1863 "Cercaria" Müller, 1773, incertae sedis Lophocercariae Cercaria cristata La Valette St. George, 1855