Heteronereis :: Heteronereis (n.) A free-swimming, dimorphic, sexual form of certain species of Nereis..
Nereid :: Nereid (n.) A sea nymph, one of the daughters of Nereus, who were attendants upon Neptune, and were represented as riding on sea horses, sometimes with the human form entire, and sometimes with the tail of a fish..
Nereid :: Nereid (n.) Any species of Nereis. The word is sometimes used for similar annelids of other families.
Nereis :: Nereis (n.) A genus, including numerous species, of marine chaetopod annelids, having a well-formed head, with two pairs of eyes, antennae, four pairs of tentacles, and a protrusile pharynx, armed with a pair of hooked jaws..
Nereites :: Nereites (n. pl.) Fossil tracks of annelids.