The adductor muscles are the main muscular system in bivalve mollusks. In many parts of the world, when people eat scallops, the adductor muscles are the only part of the animal which is eaten. Adduct
Marine blue mussel, Mytilus edulis, showing some of the inner anatomy, including the white posterior adductor muscle which is visible in the upper image, and has been cut in the lower image to allow the valves to open fully.
The umbo is the vaguely defined, often most prominent, highest part of each valve of the shell of a bivalve or univalve mollusc. It usually contains the valve's beak, the oldest point of the valve, an
A left valve of a juvenile Mercenaria campechiensis viewed from the dorsal aspect in order to show the brown-tinted lunule on the right, next to the forward facing umbo.
A side view of a whole shell of Cucullaea labiata (Lightfoot, 1786), the umbones are at the top of the image