OpisthobranchiaO*pis`tho*bran"chi*a\, Opisthobranchiata \O*pis`tho*bran`chi*a"ta\, n. pl. [NL., from Gr. ? behind + ? gills.] (Zo["o]l.) A division of gastropod Mollusca, in which the breathing organs are usually situated behind the heart. It includes the tectibranchs and nudibranchs.
|gastropods having the gills when present posterior to the heart and having no operculum: includes sea slugs; sea butterflies; sea hares|
|a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison.|
|a scrap or morsel of food left at a meal.|