RissoellidaeRissoellidae are a family of small sea snails, marine gastropod molluscs in the subclass Heterobranchia.Rissoellidae is the only family within the superfamily Rissoelloidea in the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005.GeneraGenera within the family Rissoellidae include:Cythnia Carpenter, 1864Rissoella Gray, 1847 - synonyms: Heterorissoa Iredale, 1912; Jeffreysia Alder, 1850