Nereis tridentata Webster, 1879, by original designation.

Prostomium sub-pyriform to pentagonal, one pair of frontal antennae, a pair of globose biarticulate palps, and two pairs of eyes of different shape. Peristomium with four pairs of short tentacular cirri. Pharynx with pair of jaws. Maxillary ring unarmed, oral ring with papillae on areas VI and VII-VIII. First two parapodia uniramous, remainder biramous. Notopodium represented by dorsal cirri with dorsal and median ligulae, notopodial prechaetal lobe present on anterior parapodia. Neuropodium with superior and inferior lobe forming prechaetal area; postchaetal lobe subulate to triangular, ventral ligule generally subulate. Ventral cirri short. Notochaetae homogomph spinigers; neurochaetae homogomph and heterogomph spinigers and heterogomph falcigers, those in posterior parapodia with short to long blades; anchylosed chaetae may be present. Pygidium with pair of anal cirri.