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 Monogenea see Infraclass Monogenea Suborder Monopisthocotylea Odhner, 1912 see Subclass Monopisthocotylea Superfamily Gyrodactyloidea Cobbold, 1864 1 Family Gyrodactylidae Cobbold, 1864 2 Family Dactylogyridae Bychowsky, 1933 3 Family Calceostomatidae Parona & Perugia, 1890