Resilifer
A resilifer is a part of the shell of certain bivalve mollusks. It is either a recess or a process, the function of which is the attachment of an internal ligament, which holds the two valves together.
An internal ligament is part of the hinge mechanism in certain taxonomic families of bivalve shells, such as oysters and scallops. A resilifer is the primary structure comprising the type of bivalve hinge that is known as an "isodont" hinge.