Phylum Mollusca Linnaeus, 1758 - molluscs Class Polyplacophora Blainville, 1816 [monotypic] - chitons Subclass Polyplacophora Gray, 1821 [monotypic] see Class Polyplacophora Blainville, 1816 Order Lepidopleurida Thiele, 1910 Suborder Lepidopleurina Thiele, 1910 Family Hanleyidae Bergenhayn, 1955 Genus Hemiarthrum Dall, 1876