11. For example, the great majority of tunicates, pulmonate snails, opisthobranch snails and slugs are hermaphrodites. 12. "' Cymbulioidea "'is a taxonomic holoplanktonic opisthobranch gastropod molluscs in the clade Thecosomata. 13. "' Murchisonellidae "'is a taxonomic marine opisthobranch gastropod mollusks in the superfamily Murchisonelloidea. 14. Torsion is present in all gastropods, but the opisthobranch gastropods are secondarily de-torted to various degrees. 15. "' Metarminoidea "'is a provisional taxonomic marine opisthobranch gastropod molluscs in the clade Nudibranchia. 16. Most acochlidians live interstitially in marine sands, while some have conquered limnic systems ( uniquely within opisthobranch gastropods ). 17. Because the Pulmonata are a sibling group to an opisthobranch monophyletic group and can no longer be accepted as a valid taxon. 18. He authored more than 115 scientific papers and books, including a two-volume Ray Society monograph on British opisthobranch molluscs. 19. The "'Laginiopsidae "'are a taxonomic marine opisthobranch gastropod mollusks in the suborder Gymnosomata, the sea angels. 20. Nevertheless, a few of the older terms such as " opisthobranch " and " prosobranch " are still sometimes used in a descriptive way.
