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The sea cucumber, belonging to the class of sea cucumber (Holothuroidea), is a marine echinoderm living in the seashore up to 8,000 meters, with a history of more than 600 million years, and it feeds on seabed algae and plankton. The sea cucumber is covered with spines and is widely distributed in the world's oceans. There are more kinds of sea cucumbers along the coast of South China Sea, about twenty kinds of sea cucumbers are available for consumption. Sea cucumber is famous with ginseng, bird's nest and shark's fin, and it is one of the eight treasures of the world. Sea cucumber is not only a precious food, but also a valuable medicinal herb. According to "Gleanings from the Compendium of Materia Medica", sea cucumber is sweet and salty in flavor, tonifying the kidney, benefiting the essence and marrow, taking urine, strengthening the yang and curing impotence, and its nature is warm and complementary to the enemy's ginseng, so it is called sea cucumber. Sea cucumber has the functions of improving memory, delaying gonadal aging, preventing arteriosclerosis and anti-tumor. With the popularization of the knowledge of the value of sea cucumber, sea cucumber gradually enters the people's table. The living environment determines the quality of sea cucumber.
The body is cylindrical, 10 to 20 centimeters long, and the extra-large ones can reach 30 centimeters, with dark color and many spines. The tentacles are wheel-shaped, 17 to 30, generally 20. Tentacles and hand altar sacs are well developed. Sea cucumber reproduction on earth earlier than the original fish, probably more than 600 million years ago in the Precambrian period began to exist, is the earliest existing biological species, marine living fossil called. It has survived the destruction of the earth several times and witnessed the changes of the earth. The mouth is at the anterior end, mostly favoring the ventral surface. The anus is at the posterior end, mostly favoring the dorsal surface. The dorsal surface generally has warty feet, and the ventral surface has tube feet. Endoskeleton reduced to tiny bone fragments. Many species have 5 rows of tube feet from mouth to anus. Anal pores are used for both respiration and waste expulsion. The mouth is surrounded by 10 or more retractable tentacles for feeding or burrowing. Many species can release internal organs from the anus and regenerate new ones, probably to escape from enemies. The cloaca is often alive with cryptic fish of the genus Carapus***. There are many that can release toxins that are lethal to small animals, but not life-threatening to humans.