(da Costa, 1778)
Shell tall, sharply pointed, slender, very glossy and nearly transparent; whorls flat-sided, sutures nearly invisible; no ornament. Aperture long, narrow, pointed apically; outer lip nearly straight in side view and forming shallow, open canal basally. The shell has up to 12 whorls, 3 or 4 belonging to the protoconch, but these, which are a little tumid, are often broken off. The last whorl is slender and, in apertural view, the outer lip continues the profile of the spire. Its edge is rounded, not sharp. There are a few irregular growth lines on the shell and occasional prosocline and nearly straight markings which show former positions of the outer lip. Last whorl occupies about half the shell height, aperture a third.
Up to 10 x 2.5 mm.
Yellow-white, with orange-brown bands. Usually 3 spiral bands on each whorl of spire, up to 6 on last whorl. Some brown spiral lines, especially those at the periphery, may be represented by separate streaks which curve axially.
The head is a thin ledge carrying the opening of an introvert on its underside and a pair of tentacles anteriorly. These are long and tapering, each with an eye behind and medial to its base. A pallial tentacle arises from the mantle edge on the right. In males (small, young animals) a penis with an open seminal groove on its dorsal side arises behind the right tentacle; in females (larger, older) a vestige of this persists. The foot is large but narrow, broad anteriorly, with conspicuous opercular lobes behind. The animal is white.
Ectoparasitic on echinoderms, probably ophiuroids, and live sublittorally to depths of about 200 m. The animals are consecutive hermaphrodites and the life history probably includes a free veliger stage.
Ranges from the Mediterranean to the British Isles where it has been found from south-west England, the south and west of Ireland, as far north as Shetland; not in the southern North Sea. Not common (Distr. E. glabra).