1: mantle rim whitish.
2: mantle pigmented grey/black where it forms roof of mantle cavity.
3: osphradium, tests water quality.
4: columellar muscle, attaches to shell.
5: kidney.
6: posterior oesophagus.
7: stomach.
8: digestive gland.
9: penis.
10: foot.
The ctenidium (gill), next to the osphradium, is scarcely visible through the pigment of the mantle.