The type of sponge that most frequently creates holes and burrows is Cliona celata Grant. The kind of damage caused by this sponge is found in a great variety of mollusc species but is shown here in ancient European Flat Oyster (Ostrea edulis L.) shells that have been discovered during archaeological excavations (see the photograph above); and also in modern oysters (see the photographs below). The sponge can infest the shells during the life of and after the death of the mollusc