What's the noun for nereids? Here's the word you're looking for.
nereid
(Greek) One of 50 sea nymphs who were attendants upon Poseidon (Neptune), and were represented as riding on sea horses, sometimes in human form and sometimes with the tail of a fish.
(zoology) A worm of the genus Nereis, having sharp retractable jaws and an annelid body.
“In the case of the nereid, the goods of the neutral shipper were inviolable.”
“At the mention of the commander of the nereid, all three of them gave a start.”
“A number of other volatile, low molecular mass compounds were found in the coelomic fluid of these and other nereid species and thought to play a role in their reproduction.”
