Body small and fragile.
Prostomium rounded quadrangular with four eyes in a trapezoid arrangement and two ocelli. Palps broad, oval, somewhat shorter than the prostomium. Median antenna twice as long as lateral antennae. Lateral antennae somewhat longer than the peristomium, without distinct annulation.
Tentacular cirri without distinct annulation. Dorsal cirri as long as median antenna. Ventral cirri broadly oval, as long as or slightly shorter than parapodial lobes.
Blades of compound chaetae moderately long and short on one parapodium, bidentate (E. assimilis-detail).
Body up to 20 mm long for 70 segments.
Transparent or dark orange-coloured, phosphorescent.
Atlantic, Mediterranean, English Channel up to the Straight of Dover.