Phylum Mollusca Linnaeus, 1758 - molluscs Class Bivalvia Linnaeus, 1758 - bivalves Subclass Heterodonta Neumayr, 1884 see Clade Heterodonta Neumayr, 1884 Order Chamida see Order Venerida Gray, 1854 Superfamily Mactroidea Lamarck, 1809 Family Mactridae Lamarck, 1809 - surf clams Subfamily Lutrariinae Gray, 1853 Genus Heterocardia Deshayes, 1855