sea urchin test found on the flood line at the north sea beach

aan animal aquatic ashore beach coast coastline cordatum detail diagonal echinidae echinocardium echinus egmond esculentus europe fauna flood invertebrates line macro marine nature netherlands noordzee north pattern pools potato round sand sea seafront seashell seaside shell shellfish shield shore skelet skeleton skeletton spheral sphere spherical summer symmetry test texture the urchin washed water white zee