- A minor phylum of mesozoan worms which are internal parasites of a range of marine invertebrates.More example sentences
- They are now believed to be made up of two, possibly unrelated, groups: the Dicyemida and Orthonectida.
- As it turns out, the Orthonectida are almost certainly metazoans, particularly under our stem group definition; but it's anyone's guess whether they, or any other members of the mysterious Mesozoa, are also bilaterians.
modern Latin (plural), from Greek orthos 'straight' + nektos 'swimming' (see nekton).
More definitions of OrthonectidaDefinition of Orthonectida in:
- The US English dictionary