Comarmondia gracilis

(Montagu, 1803)

Description (shell):
Shell an elongate cone of up to eleven (commonly nine or ten) tumid whorls; sutures deep, accentuated by a broad, slightly concave subsutural band. Sculpture of broad, opisthocline costae, numerous spiral striae and fine growth lines. Costae do not cross subsutural band nor extend below periphery of last whorl. Spiral striae strap-like, separated by shallow, minutely granular grooves; spiral striae lower and narrower on subsutural band, where granulation is particularly conspicuous. Protoconch of three or four whorls; initially smooth, developing strong peripheral keel, making an abrupt junction with the teleoconch. Aperture elongate-oval, drawn out basally into siphonal canal, which flares slightly and to right at base. Anal sinus a deep, narrow arch. Outer lip thin, crenulate, with a varix set back from margin; internally thickened in older shells, with toothed ridge. Inner lip reflected over columella; in older shells a prominent tooth on base of last whorl at entrance to anal sinus.

Up to 26 x 10 mm.

Light horn coloured, often with darker subsutural band and with paired light and dark band near periphery of last whorl; ribs pale.

Cephalic tentacles thick, with eyes near the tip. Siphon short, not projecting far from canal in active animals. Males with a penis behind the right tentacle. Foot yellowish with white speckles, with double edged anterior margin and lateral horns; no operculum.

Sublittoral, on muddy or sandy gravel at 7-150 m.

Distributed from Mediterranean to Orkneys; on western shores of British Isles, western Channel basin; recorded from Moray Firth but apparently absent from the rest of North Sea (Distr. Com. gracilis).