Shape more or less homogeneous, sometimes a definite constriction between first and second region, and partly swollen third region. Pallial cavity generally enlarged, bearing distinct orange brown secretions. The number of one type of scales (several or many), spread over a certain region of body, depends largely on size and age. Only small squamiform scales and bomb-like spicules without more definite keel (C. nitidum-scales). Foot shield is generally round in shape, mouth in its deep frontal cleft (C. nitidum-detail). Dorso-terminal sense organ not extending as far as pallial integument border. Digestive midgut gland long. Ctenidia is large and provided with up to 25 alternating lamellae at each side. Joined cerebral ganglia is provided with a median lobe (lobus impar) at posterior face.
Animals with ctenidia range from 3 to 80 mm, usually only up to 30-40 mm.
One pair of relatively large denticles; basal plate heavily strengthened in transversal pattern, flanked by two lateral supports with distal strengthenings.
Brownish grey veiled by a silver lustre, originating from the clinging scales; first body region shows a slight pinkish tinge and the ctenidia glimmer reddish. The bell-shaped pallial region is covered with orange-brown incrustations of secretions.
Muddy to sandy bottoms in depths of 8 to 900 m. A marked inhabitant of shallower open sea (20-150 m), typically represented in the North Sea and in the Kattegat. Deeper records are scarcer, and in the deep-sea the species is superseded by other Caudofoveata. It is a representative of the boreal offshore muddy sand and mud associations and reaches there an abundance of up to 1 specimen/m2 or locally even more.
Eastern Kattegat, the North Sea, Scandinavian coast from Öresund to Varangerfjorden, the Faroe Islands, Iceland, Jan Mayen, Spitzbergen, and eastern Greenland (Distr. C. nitidulum).