Shell removed . Organs discernible through intact, translucent mantle.
1: operculum.
2: pale dorsal surface of epipodium.
3: dark ventral surface of epipodium.
4: sole of foot.
5: side of foot.
6: head.
7: anterior of mantle.
8: ctenidium (gill).
9: osphradium.
10: efferent branchial vessel.
11: left kidney, attached to mantle.
12: anterior aorta.
13: left (anterior) auricle of heart.
14: digestive gland.
15: gonads (inactive; in September). Colour similar in both sexes,
except February- May when ovaries green and testes pink or
cream. www.marlin.ac.uk/species/detail/1324
16: rectum (opened) running through the ventricle of the heart.
17: columellar muscle.
Photograph interpreted with Fretter and Graham (1994, in Crothers, 2001, .).
Menai Strait, Wales. September 2016.