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 Gymnosomata Blainville, 1824 - naked pteropods see Suborder Gymnosomata Blainville, 1824 Family Hydromylidae Pruvot-Fol, 1942 (1862) [monotypic] 1 Genus Hydromyles Gistl, 1848