(McIntosh, 1873-74)
Description:
The body reaches a length of up to 15 cm and is 2-4 mm or more wide. It is characteristically dorsoventrally flattened with thin translucent or opaque margins. Anteriorly the head tapers to a bluntly rounded point, posteriorly the body is either more or less uniform in width or gradually broadens throughout its length, terminating bluntly and bearing a short but distinct colourless caudal cirrus (C. fuscus-2). There are 4-13 eyes on each side of the head.
The general colour is a pale yellowish, greyish-brown or pinkish tinge, dorsally speckled lightly and indistinctly with red, brown or greenish-grey. Often the anterior dorsal surface is more darkly pigmented than the rest of the body, although in larger individuals this colouration tends to spread throughout the animal's length. There is usually a distinct reddish hue in the cerebral ganglionic region, and the lateral nerve cords may appear as pinkish longitudinal lines in the intestinal regions. The cephalic slits too may be internally tinged pink or red (C. fuscus-old). The body is commonly marked by pale transverse lines or furrows (C. fuscus). Dermis with insignificant amounts of connective tissue which do not separate the glandular region from the body wall muscles. Proboscis with three muscle layers, the outer longitudinal zone peripherally incomplete, with one muscle cross.
Cerebratulus fuscus may swim actively for a few minutes if disturbed.
Habitat:
Occasionally found intertidally, but more commonly obtained by dredging at depths to about 50 m but it has been found (off Portugal) as deep as 1590 m. Typically living in sandy sediments or amongst shelly gravel, it may sometimes be obtained from Laminaria holdfasts, with oyster shells or in mud.
Distribution:
From Alaska and Florida in North America to Greenland, European waters, including the Mediterranean and South Africa.