Gastropoda Anaspidea Basommatophora Nudipleura Hypsogastropoda Archaegastropoda Caenogastropoda Mesogastropoda Archaeopulmonata Cephalaspidea Heterostropha Neotaenioglossa Notaspidea Nudibranchia Phanerobranchia Sacoglossa Systellommatophora Thecosomata