Oyster is a bivalve mollusk, belonging to the family Ostreaceae or the family Avinidae, which is distributed in the coastal waters of temperate and tropical oceans. Vertebrates and malformed animals are sometimes called echinoderms and saddle oysters, respectively. Shell of oyster, oyster in Dalian Bay or oyster near the river (M-plum). It can be harvested, fleshed, washed and dried all year round. Category: Pinggan Xifeng Medicine Latin: Oyster alias: Oyster mussel, left-handed oyster, oyster shell, oyster shell, oyster yellow, oyster, fresh oyster and ancient oyster (b √). Oysters have been used for food since 2000 BC. Pearls can be produced in the shell of pearl oyster. The two shells of oysters are different in shape, and the surface is rough and dark gray; The middle part of the upper shell protrudes; The lower shell is attached to other objects, with large volume, quite flat and smooth edges; The inner surfaces of both shells are white and smooth. The two shells are connected at the narrower end by an elastic ligament. There is a powerful adductor muscle in the middle of the shell to resist the tension of the ligament. When the shell is slightly opened, water is introduced into the shell through the wave motion of cilia (the water flowing through it can reach 2-3 gallons per hour) to filter microorganisms. Birds, starfish, snails and fish including rays all eat oysters. Oysters and snails are widely distributed. It often drills a small hole in the oyster shell with its tongue and sucks its living tissue. Oysters are mostly hermaphroditic, but some are hermaphroditic. Edible oysters (Ostrea edulis) can change their sex according to the season or with the change of water temperature (rhythmic hermaphroditism). Oysters breed in summer. Some kinds of eggs are fertilized in water, while others are fertilized in females. The hatched larvae are spherical and ciliated, and are permanently fixed to other objects after swimming for several days. Harvest after 3 ~ 5 years. True oysters (Ostreaceae) include three genera: oyster, oyster and oyster with dense teeth. Edible oysters are distributed from Norway to Morocco and from the Mediterranean to the Black Sea. Androgyny; It is 8 cm (about 3 inches) long. O. lurida is a yellowish oyster, which is 7.5 cm (3 inches) long along the Pacific coast of North America. O. frons is also very common. North American oyster (C. virginica, namely Virginia oyster or Virginia thick oyster) originated from the Gulf of St. Lawrence to the West Indian Ocean Islands and has been introduced to the west coast of North America; Length 15cm (6 inches); A woman can ovulate as many as 50 million at a time; It has the greatest commercial value among edible shellfish in North America. There are Portuguese oysters (C. angulata) along the coast of western Europe. Japanese oyster C. gigas is the largest oyster with a body length of 30 cm (1 ft). Oysters can be eaten raw, cooked, canned or smoked, and frozen in small quantities. The popular varieties of cowpea thick oyster are: blue point thick oyster and forest haven thick oyster (named after blue point area and forest haven bay area of Virginia Governor's Island respectively). Popular edible oyster varieties include British Colchester oyster and French Marena oyster. If a foreign body invades the shell of an oyster, the oyster will secrete nacre to wrap the foreign body layer by layer to form pearls. Pearls produced by eating oysters are dull in color and of low value. Only a few oriental varieties, especially the Pearl of the Persian Gulf (Meleagrina vulgaris), produce the highest quality pearls. Pinctada is mainly distributed in 8 ~ 20? (48 ~ 120 feet) deep seabed. Pearls are mostly collected from oysters over 5 years old. Small pearls are implanted into mother-of-pearl by hand to form cultured pearls around them. Most pearl farming is carried out in the coastal waters of Japan or Australia.