Pecten maximus, common name the "great scallop" or "king scallop", is a species of scallop, an edible saltwater clam, a marine bivalve mollusk in the family Pectinidae, the scallops. This is the type species of the genus. This species may in fact be conspecific with Pecten jacobaeus, the "pilgrim's scallop", which has a much more restricted distribution. 
The oil company Royal Dutch Shell derives its highly recognizable logo from this species.
Live individual of Pecten maximus
on the right, next to Ostrea edulis