A scale-worm with an elliptical body. Dorsal and ventral surfaces smooth.
Prostomium bilobed, with a peak on each lobe, a median antenna, a pair of lateral antennae, and a pair of palps with 6 rows of papillae. Two pairs of eyes, the anterior pair near the line of greatest width and the posterior pair in front of the rear margin. First segment bearing 2-5 stout chaetae and a pair of dorsal and ventral tentacular cirri (E. nodosa-head). Scales overlap, completely covering the body. Scales thick, kidney-shaped, the outer margins fringed with papillae and surfaces covered with coarse, wart-like protuberances, with a row of large and medium spined tubercles on the posterior edge, and elsewhere bifid and multi-spired small tubercles (E. nodosa-scale). On segments with scales, small lobes are situated towards the dorsal mid-line. Notopodia are small mounds with a ventral acicular ligule, and numerous chaetae in regular rows. Notopodial chaetae stout with rows of spines and blunt tips. Neuropodia well developed with a dorsal acicular ligule and abundant chaetae in distinct rows (E. nodosa-parapodium). Neuropodial chaetae with several rows of spines on the swollen terminal end and unidentate tips.
Up to 90 mm for 37 chaetigers.
Sublittoral to 1260 m, amongst algae or on hard bottoms. Reported as commensal with pagurid crustaceans on the Alaskan shelf.
Arctic, North Pacific, North Atlantic to English Channel, probably whole North Sea, Skagerrak, Kattegat, up to northern Öresund.