carditidæ

Century Dictionary and Cyclopedia

1. A family of Pelecypoda with a cockle-like shell, external parivincular ligament, and fully developed hinge with long posterior cardinal tooth. The genera are all marine. They began their existence in the Triassic and have continued to the present.
2. A family of bivalve mollusks of the order Evlamelli-branchiata. They have a single mantle-fusion, branchiæ large and unequal, the foot keeled and often byssiferous, and the shell radiately grooved. The family includes the genera Cardita, Carditella, Venericardia, and others.