(Linné, 1758)
Description (shell):
Shell of mature animals readily distinguished by palmate extension to the outer lip; no such extension in shells with less than eight whorls. Spire tall, whorls tumid, with crescentic costae and fine, flat spiral striae; apical whorls finely decussate or with spiral striae only. Last whorl of mature animals with three prominent spiral ridges set with stout tubercles; ridges extend on to palmate outer lip but are not tuberculate at this point. Aperture in mature shells dominated by palmate outer lip; uppermost process fuses with lower part of spire, extending to antepenultimate whorl; basal process curved upward towards aperture (in juveniles this is the only process and resembles a sharply pointed siphonal canal).
Size:
Up to 4.2 x 2.8 cm.
Colour:
Cream or sandy coloured, sometimes with purplish stain on back of last whorl; apertural surfaces pearly white (A. pespelecani-drawing).
Animal:
Snout long; cephalic tentacles long, cylindrical, with eyes on lateral bulges at base; males with thick, tentaculiform penis behind right tentacle. Foot with double-edged anterior margin; operculum elongate-oval, set across the foot.
Habitat:
Sublittoral; locally common on mud and muddy sand to 180 m.
Distribution:
Distributed from Mediterranean to northern Norway and Iceland; not common (Distr. A. pespelecani).