Strepsiduridae Family Turbinellidae Family Volutidae Family Volutomitridae Superfamily Olivoidea Family Olividae Family Olivellidae Superfamily Pseudolivoidea Family Pseudolividae Family Ptychatractidae Superfamily Conoidea Family Conidae Family Clavatulidae Family Drilliidae Family Pseudomelatomidae Family Strictispiridae Family Terebridae Family Turridae Superfamily Cancellarioidea Family Cancellariidae Clade Heterobranchia Contains the informal groups Heterobranchia, Opisthobranchia and Pulmonata Informal group "Lower Heterobranchia" (= Allogastropoda) Unassigned to a superfamily Family Cimidae † Family Dolomitellidae † Family Heterosubulitidae † Family Kuskokwimiidae † Family Misurinellidae Family Orbitestellidae Family Tjaernoeiidae Family Xylodisculidae Superfamily Acteonoidea Family Acteonidae † Family Acteonellidae Family Aplustridae Family Bullinidae † Family Zardinellidae Superfamily Architectonicoidea Family Architectonicidae † Family Amphitomariidae † Family Cassianaxidae Superfamily Glacidorboidea Family Glacidorbidae Superfamily Mathildoidea Family Mathildidae † Family Ampezzanildidae † Family Anoptychiidae † Family Gordenellidae † Family Tofanellidae † Family Trachoecidae Superfamily Nerineoidea † Family Nerineidae † Family Ceritellidae † Family Nerinellidae Superfamily Omalogyroidea Family Omalogyridae † Family Studraxidae Superfamily Pyramidelloidea Family Pyramidellidae Family Amathinidae † Family Heteroneritidae Family Murchisonellidae Superfamily Ringiculoidea Family Ringiculidae Superfamily Rissoelloidea Family Rissoellidae Superfamily Streptacidoidea † Family Streptacididae † Family Cassianebalidae Superfamily Valvatoidea Family Valvatidae Family Cornirostridae Family Hyalogyrinidae † Family Provalvatidae Informal group Opisthobranchia Contains the clades Cephalaspidea, Thecosomata, Gymnosomata, Aplysiomorpha, Sacoglossa, Umbraculida, Nudipleura and the groups Acochlidiacea and Cylindrobullida. Clade Cephalaspidea Superfamily Bulloidea Family Bullidae Superfamily Diaphanoidea Family Diaphanidae Family Notodiaphanidae Superfamily Haminoeoidea Family Haminoeidae Family Bullactidae Family Smaragdinellidae Superfamily Philinoidea Family Philinidae Family Aglajidae Family Cylichnidae Family Gastropteridae Family Philinoglossidae Family Plusculidae Family Retusidae Superfamily Runcinoidea Family Runcinidae Family Ilbiidae Clade Thecosomata Superfamily Cavolinioidea Family Cavoliniidae Family Limacinidae † Family Sphaerocinidae Superfamily Cymbulioidea Family Cymbuliidae Family Desmopteridae Family Peraclidae Clade Gymnosomata Superfamily Clionoidea Family Clionidae Family Cliopsidae Family Notobranchaeidae Family Pneumodermatidae Superfamily Hydromyloidea Family Hydromylidae Family Laginiopsidae Clade Aplysiomorpha (= Anaspidea) Superfamily Aplysioidea Family Aplysiidae Superfamily Akeroidea Family Akeridae Group Acochlidiacea Superfamily Acochlidioidea Family Acochlidiidae Superfamily Hedylopsoidea Family Hedylopsidae Family Ganitidae Family Livorniellidae Family Minicheviellidae Family Parhedylidae Family Tantulidae Superfamily Palliohedyloidea Family Palliohedylidae Superfamily Strubellioidea Family Strubelliidae Family Pseudunelidae Clade Sacoglossa Subclade Oxynoacea Superfamily Oxynooidea Family Oxynoidae Family Juliidae Family Volvatellidae Subclade Placobranchacea Superfamily Placobranchoidea Family Placobranchidae Family Boselliidae Family Platyhedylidae Superfamily Limapontioidea Family Limapontiidae Family Caliphyllidae Family Hermaeidae Group Cylindrobullida Superfamily Cylindrobulloidea Family Cylindrobullidae Clade Umbraculida Superfamily Umbraculoidea Family Umbraculidae Family Tylodinidae Clade Nudipleura Subclade Pleurobranchomorpha Superfamily Pleurobranchoidea Family Pleurobranchidae Subclade Nudibranchia Contains the clades Euctinidiacea and Dexiarchia Unassigned to superfamily Family Rhodopidae Clade Euctenidiacea (= Holohepatica) Contains the subclades Gnathodoridacea and Doridacea Subclade Gnathodoridacea Superfamily