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 Distome cercariae 'Leptocercous' cercariae 'Echinostome' cercariae 1 Cercaria echinata Siebold, 1837