Definition of Opisthobranchia in English:

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Pronunciation: /əˌpɪsθə(ʊ)ˈbraŋkɪə/

plural noun

A group of molluscs which includes the sea slugs and sea hares. They have a small or absent shell and are typically brightly coloured with conspicuous external gills.
  • Subclass Opisthobranchia, class Gastropoda.
Example sentences
  • The latter group includes radically modified animals, the Opisthobranchia and Pulmonata, which undergo detorsion and essentially re-evolve bilateral symmetry.
  • In fact, as with the Opisthobranchia, shell reduction has occurred independently a number of times in different lineages.
  • However, as with Tritonia, many other members of the subclass Opisthobranchia also exhibit swimming behavior.



Pronunciation: /əˈpɪsθə(ʊ)braŋk/
Example sentences
  • The opisthobranchs include the sea slugs and their relatives the sea hares, sea butterflies, canoe shells, and others.
  • Despite their apparent common origin and similarities in nervous system organization, the opisthobranchs display a wide variety of body forms and locomotory behaviors.
  • Thus, the opisthobranchs exhibit a great diversity of swimming behaviors.


Modern Latin (plural), from opistho- 'to the rear' + brankhia 'gills'.

For editors and proofreaders

Line breaks: Opistho|bran¦chia

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