Drill holes in Mollusca, attributed to Naticidae prey action from Alt Penedes (Catalunya) Miocene are studied, and a list of molluscan species from La Pedrera (Sant Llorenc; d'Hortons) is presented. Differences found in drill hole sizes observed in three molluscan species lead us to conclude that predators choose prey according to ornamentation and thickness of prey shell, although no clear selection of drill hole situation is apparent. Drilling activity on unoccupied shells is not observed in any case.