Marcia recens is a species of mussels in the Phylum Mollusca. It has durable shells that serve as a protective covering against potential threats and changes in the surrounding environment. Generally, clams have four main body parts: the head, foot, visceral mass, and mantle. The mantle is a unique organ found exclusively in animals of the Phylum Mollusca, responsible for constructing the shell that encases the visceral mass.