Thylacodes arenarius

The Thylacodes arenarius is an odd gastropod of the Mediterranean and adjacent zones of the Atlantic, up to the Canary Islands, the Channel and the North Sea. When adult it lives fixed on the rocks or on other solid substrata in a tubular shell without operculum 10-15 mm long. It grows turning irregularly to the right, like a corkscrew. The visible part of the body is red with golden spots and inside the tube is pearly just to tell us that it is a shell and not an annelid. It nourishes fishing plankton with a long mucilaginous filament that then retracts with the victims stuck © Giuseppe Mazza