sea urchin

noun

• a marine echinoderm that has a spherical or flattened shell covered in mobile spines, with a mouth on the underside and calcareous jaws. Many species are harvested for food.

  • Class Echinoidea: several families and genera, and numerous species, including the Atlantic purple sea urchin (Arbacia punctulata, family Arbaciidae) and the green sea urchin (Strongylocentrotus drobachiensis, family Strongylocentrotidae)