Body long and fragile.
Prostomium rounded quadrangular, bilobed, with four lensed eyes, the anterior pair the largest. Prostomium with 2 antennae and 2 annulated palps, thicker and a little longer than the lateral antennae and with 2 rings.
Lateral antennae threadlike and a little longer than the prostomium. Median antenna absent.
8 pairs of annulated tentacular cirri on 4 segments. Parapodia subbiramous. Dorsal and ventral cirri annulated.
Tentacular cirri placed on long cirrophores. Dorsal cirri even longer than the longest tentacular cirri. Notopodia only with 2 or 3 aciculae on the basis of the dorsal cirri.
Neuropodia blunt conical with broad rounded postchaetal and 2-3 folded prechaetal lobes with usually 3 aciculae (K. cirrata-detail).
Pharynx with 40 or more thread-like terminal papillae, without jaws.
Body up to 75 mm for 70 segments.
Very variable, yellow, yellowish-brown, light or darker pink to dark red. Cirri whitish.
Atlantic between Iceland and South Africa, Mediterranean, English Channel, North Sea up to Bay of Kiel.