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 Acteonacea d'Orbigny, 1835
see Superfamily Acteonoidea d'Orbigny, 1843
Family Aplustridae Gray, 1847
Genus Hydatina Schumacher, 1817
Subgenus Hydatina (Aplustrum) Schumacher, 1817
see Genus Aplustrum Schumacher, 1817