Disarticulated opercular valves (treated with bleach). Different faces of the right tergum: 1, 2, & 4, and right scutum: 3 & 5. Faces 2 and 3 are visible on a live animal when the operculum is closed. Cavity in tergum (6) accommodates a protrusion of the scutum (7). North Wirral coast, Cheshire, England. February 2012.