Man Holding Sea Cucumber
An illustration of a man holding a sea cucumber. The sea cucumber (also known as trepang and sea slug) is an echinoderm of the class Holothuroidea, with an elongated body and leathery skin, which is found on the sea floor worldwide. It is so named because of its cucumber-like shape. The body contains a single, branched gonad. Like all echinoderms, sea cucumbers have an endoskeleton just below the skin, calcified structures that are usually reduced to isolated microscopic ossicles (or sclerietes) joined by connective tissue. These can sometimes be enlarged to flattened plates, forming an armor.