This species may reach a length of 1 m and width of 25 mm or
more. The worms, however, are exceptionally contractile and may
be less than half their extended length (C. marginatus). The
head is sharply tapered and bluntly pointed, with wide cephalic
furrows (C. marginatus-detail). Although it is stated that eyes
are absent from this species, pigmented eyes are present. Their
small size, however, makes them easily overlooked in living
individuals. The body behind the mouth is dorsoventrally
compressed, with sharp lateral margins. Transverse epidermal
folds of varying sizes often give the nemerteans an irregularly
wrinkled appearance, particularly when the body is contracted.
The transparent caudal cirrus is slender. The colour is
typically a uniform greyish-brown with whitish or transparent
lateral margins through which the pink coloured lateral nerve
cords are often visible. Younger individuals are generally
paler, and the dorsal pigmentation of older animals may be
somewhat darker than that of the underside.