Phylum Mollusca Linnaeus, 1758 - molluscs
Class Gastropoda Cuvier, 1795 - snails and slugs
Subclass Opisthobranchia Milne-Edwards, 1848 - opisthobranchs
see Order Opisthobranchia Milne-Edwards, 1848
Order Cephalaspidea Fischer, 1883
Superfamily Acteonoidea d'Orbigny, 1843
Family Hydatinidae Pilsbry, 1895, nom. illeg.
see Family Aplustridae Gray, 1847
Genus Micromelo Pilsbry, 1895