Phylum Mollusca Linnaeus, 1758 - molluscs Class Gastropoda Cuvier, 1795 - snails and slugs Subclass Heterobranchia Burmeister, 1837 [monotypic] see Superorder Heterobranchia Burmeister, 1837 Order Heterostropha Fischer, 1885 Superfamily Rissoelloidea Gray, 1850 Family Rissoellidae Gray, 1850 [monotypic] Genus Rissoella Gray, 1847 Subgenus Rissoella Gray, 1847