| Aspect: | Very often covered in camouflaging elements (sponges, algae etc) its valves have distinct deep-V interlocking edges. |
| Population: | Very difficult to spot, but quite widespread. |
| Notable feature: | Deep-V edges |
| Environment: | Usually found in open waters, atop boulders, or attached to old buoy mooring lines and wreck masts |
| Behaviour: | Valves will instantly shut if approached too closely. |