‖n. [ NL. See Hetero-, and Nereis. ] (Zool.) A free-swimming, dimorphic, sexual form of certain species of Nereis. [ 1913 Webster ]

☞ In this state the head and its appendages are changed in form, the eyes become very large; more or less of the parapodia are highly modified by the development of finlike lobes, and branchial lamellæ, and their setæ become longer and bladelike. [ 1913 Webster ]

‖prop. n.; pl. Nereides [ L. ] 1. (Class. Myth.) A Nereid. See Nereid. [ 1913 Webster ]

2. (Zool.) 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. [ 1913 Webster ]