Phylum Mollusca Linnaeus, 1758 - molluscs Class Cephalopoda Cuvier, 1795 - cephalopods Subclass Nautiloida Agassiz, 1848 see Subclass Nautiloidea Agassiz, 1848 Order Nautilida Agassiz, 1848 Suborder Nautilina Agassiz, 1848 Superfamily Nautiloidea Blainville, 1825 Family Nautilidae Blainville, 1825 Genus Eutrephoceras Hyatt, 1894