noun
gastropods having the gills when present posterior to the heart and having no operculum: includes sea slugs; sea butterflies; sea hares
• Syn: ↑Opisthobranchia
• Hypernyms: ↑class
• Member Holonyms: ↑Gastropoda, ↑class Gastropoda, ↑Gasteropoda, ↑class Gasteropoda
• Member Meronyms: ↑Nudibranchia, ↑order Nudibranchia
Useful english dictionary. 2012.