Solid shell up to 6.5cm in length. The colour is variable and can include white, red, pink, orange, yellow, green, brown and purple and various shades and patterns of these.The shell surface is sculptured with ribs which possess spines.
- 25 to 35 similar ribs on both valves
- Often thorn like plates on the ribs
- The posterior ear is larger than the anterior one
Very common. Distributed from Denmark to the Iberian Peninsula and into the Mediterranean.