Pencil sea urchin (Diadema setosum) on cedar and silver stand.
Sea urchins are echinoderms, what means “thorny skin”. The starfishes, the sea cucumbers and the dollars of sand are all echinoderms.
Sea urchins possess a body in the form of dome armed with mobile thorns. Between these thorns, we find five rows of feet provided with suction cups which sea urchins use to climb or to hang on rocks. The sea urchin pencil is characteristic of the central pacific and distinguishes itself by its red color and its spines in the form of sticks. They were formerly used as pencils of slate, where from the name.