(Montagu, 1803)
Description (shell):
Shell rather elongate, with six or seven turreted whorls; turreting enhanced by sloping, subsutural shelf. Sculpture of costae, spiral striae and growth lines; 12-16 ribs on each whorl, on last whorl fading towards base; costae change direction abruptly on crossing subsutural shelf. Spiral striae numerous, interacting with growth lines to give fine decussation between costae; striae and costae sometimes interact to give bolder decussation especially on upper whorls. Protoconch conspicuous, initially smooth, subsequently developing spiral striae. Aperture elongate, with slight anal sinus at position of subsutural shelf, outer lip thin, inner lip angulate where it extends from base of last whorl to form one wall of siphonal canal (O. turricula-drawing).
Size:
Up to 20 x 9 mm, commonly 12 x 5 mm.
Colour:
Pale buff or white (O. turricula).
Animal:
Distal one-third of tentacles narrow, eyes at junction with broader basal portion. Siphon extends long way from canal in moving animals; foot with small, oval operculum.
Habitat:
Sublittoral, on sandy bottoms from 20 to 200 m.
Distribution:
Circumboreal, more common in the northern than in the southern part of the North Sea (Distr. O. turrita).