(Linné, 1758)
Description (shell):
Shell solid, conical, slightly cyrtoconoid, with five or six slightly tumid whorls; last whorl angulate, base flat. Sculpture of fine spiral ridges and grooves, 10-17 (commonly 13-14) on base of last whorl, traversed by prosocline, S-shaped, growth lines. Umbilicus small, oval or egg-shaped, deep. Umbilical cavity revealed as a small pinhole at apex of eroded shells. In populations of from the Channel coasts of Devon and Cornwall many individuals have been found in which the umbilicus is either wholly or partially occluded by the inner lip. This tendency towards umbilical occlusion appears to increase with age (G. cineraria-drawing).
Size:
Up to 16 x 15 mm.
Colour:
Greyish or straw coloured with many thin opisthocline stripes of reddish-brown or purple resulting from alignment, or near alignment of pigmented spots on successive spiral striae.
Animal:
Sensory papillae on snout, cephalic tentacles and three pairs of epipodial tentacles. Foot oval, fringed with papillae, without anterior pedal gland.
Habitat:
On rocky shores, on weed and under stones, below LWNT (may occur higher in rock pools, especially in north), extending sublittorally to about 130 m.
Distribution:
Distributed from Gibraltar to north Norway and Iceland. Abundant on all British coasts and Helgoland (Distr. G. cineraria).