Phylum Mollusca Linnaeus, 1758 - molluscs Class Bivalvia Linnaeus, 1758 - bivalves Subclass Heterodonta Neumayr, 1884 see Clade Heterodonta Neumayr, 1884 Order Myida Stoliczka, 1870 Suborder Myina Stoliczka, 1870 see Superfamily Myoidea Lamarck, 1809 Superfamily Hiatelloidea Gray, 1824 [monotypic] 1 Family Hiatellidae Gray, 1824 - geoducks