Prostomium oval, a little longer than wide. Nuchal slits almost parallel, straight, long, almost of the same length as the head (C. torquata-anterior end).
4th chaetiger with collar. Anterior 4-8 chaetigers with complete glandular bands, posterior segments with glandular areas around the parapodia. No spines.
Pygidium with a short funnel, with 22-26 equal cirri.
Up to 150 mm for 18 chaetigers.
Straight, cylindrical, often forked, covered with sand or shell fragments.
Greenish-brown to reddish, with dark brown or red glandular areas.
Southern North Sea, Newcastle. Introduced from North America.