echinoidea

listen to the pronunciation of echinoidea
English - Turkish
ekinoidler (suda serbest yaşayan ekinoderm sınıfı)
English - English
See Spatangoid, Clypeastroid
They have a calcareous shell, usually more or less spheroidal or disk-shaped, composed of many united plates, and covered with movable spines
The class Echinodermata which includes the sea urchins
sea urchins and sand dollars