(Brocchi, 1814)
Description (shell):
Shell solid, glossy and translucent; sculpture of transverse lines of dots and dashes, crossed by finer longitudinal lines; too small for animal to withdraw into completely.
Size:
Up to 15 mm, length about 1.5 times width.
Colour:
White to pale yellow, usually with brownish markings.
Animal:
Body grey-white with yellowish-brown tinge; only cephalic shield, enlarged parapodial lobes, and posterior mantle lobe visible. Head indented anteriorly; produced posteriorly into smoothly rounded tentacular processes which point straight back, overlapping shell, not flaring outwards.
Habitat:
In muddy sand; sublittoral, to 1500 m.
Distribution:
Not in the southern North Sea (Distr. R. utricula).