Cliona lobata

Erling Svensen Do anybody knows this Cliona and confirm the specie? From South West Norway, 30 meters deept.

Erling Svensen thanks, Dawn Watson

David Kipling There seem to be quite a lot of Cliona species worldwide, many (?all) boring. C. celata is unusual in forming that massive form but that doesn't help here!

David Kipling Erling, is this boring out of rock, or a shell? And how big are those discs?

Erling Svensen They are boring out from a Arctica islandica. The discs are aprox. 3 millimeter across

David Kipling Cliona lobata bores in just shells, whereas celata bores shells and rock. However it sounds too big for lobata, which is supposed to have exhalent papillae 1.6mm max across. Cliona celata thus sounds best bet.

David Kipling http://species-identification.org/species.php?species_group=sponges&id=185