Strongylocentrotrus Droebachiensis Sea Urchin with purple shades XXL from Vietnam.

Sea urchins belong to the echinoderm tribe, the Echinodermata. These invertebrates are found in almost all seas and can of course be recognized by their spines. There are spherical, heart-shaped and disc-shaped sea urchins. In the range of Coral and Fish Store you will find different types of sea urchins, such as the Diadema Antillarum and the Mespilia Globulus. Sea urchins have armor covered with spines, which they use for locomotion as well as protection. The spines are attached with a ball joint and are therefore movable. Between the spines are feet or suction cups, with which the sea urchin can also move. The rest of the body consists of calcium plates that protect the organs as well as possible. Most sea urchins have poisonous spines with which they can defend themselves. In principle, this poison is not dangerous for humans, but a prick from a thorn can really hurt. There are also species that are very poisonous. The sea urchin's mouth is on the underside of the body. For example, they can scrape food off rocks with their five-pointed limestone plates. Around these limestone plates are a kind of gripping tongs with which they bring their food to their mouth. Sea urchins and sea apples (sea burdock, heart urchin) are spiny aquatic invertebrates. They form the class of the Echinoidea which belongs to the phylum of the Echinodermata (echinoderms). Sea urchins are usually more or less spherical, heart-shaped, or disc-shaped and have a lower mouth. They have a hard shell that is usually covered with spines. The armor consists of small plates on which there are knobs on which the spines are movably attached by means of a ball joint. The spines serve for locomotion in many species. Some species burrow in using the spines. The spines also have a protective function. Some species can even emit poison. Between the spines are short-stalked, divergent pedicellariae. These also serve for defense and for keeping the skin clean. See also: sand dollar. Regular sea urchins (Regularia such as Psammechinus, Echinus) have 10 pairs of placed rows of suction feet from the mouth (underside) to the anus (on the back, at the top = aboral). The plates through which these suction feet emerge are called ambulacral plates. The other plates are the adambulacral plates. All Regularia have a built-in chewing device: Aristotle's lantern. In the irregular sea urchins (Irregularia, such as Echinocyamus, Echinocardium) the suction feet are located at the top of the shell, where they form a flower or star-shaped figure. In this group, the anus is on the side and the mouth on the bottom. Nor do they have an Aristotle's lantern. The Sea Urchins usually live on plant food or detritus. Some species also take animal food. They usually bring their food to the mouth with tube feet and spines.