Phylum Mollusca Linnaeus, 1758 - molluscs 1 Order †Merismoconchida Yu Wen, 1979 2 Class Aplacophora von Ihering, 1876 - aplacophorans see Phylum Mollusca Linnaeus, 1758 3 Class Polyplacophora Blainville, 1816 - chitons 4 Class Monoplacophora Odhner, 1940 - monoplacophorans 5 Class Gastropoda Cuvier, 1795 - snails and slugs