Black Sea Urchin. Erizo de mar negro

Youth. It is a medium-sized sea urchin, characterized by its deep black color and its haemispherical shape. All of its spines are roughly the same size (no "secondary spines"), and worn erected (never dishevelled when in the water). The anus on the top is surrounded by 4 plates forming an anal valve. The oral face is nearly naked, the mouth being surrounded by soft, dark-greenish skin.