19 Littorina compressa male removed from shell. Shell height 8mm. North coast of Anglesey, Wales. March 2015.

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.

Full SPECIES DESCRIPTION with links to images at: flic.kr/p/pMWCmc

Sets of OTHER SPECIES at: www.flickr.com/photos/56388191@N08/collections/

Done