Green mussel, namely mussel, is also called "sea red" in some parts of Bohai Sea (but this word is called crab in Tianjin). After drying, it is called "mussel". It is distributed in the southern part of the East China Sea, the coast of the South China Sea and the Bohai Sea. They often live in the intertidal zone to the shallow seabed, and can be found in driftwood, ship bottom and other places besides rocks on the seashore.
Qingkou shell is large, which can be as long as 13 ~ 14 cm in the south, but it is usually less than 8 cm in the Bohai Sea area in the north. The length of the shell is twice the height of the shell. The top of the shell is located at the front end of the shell, namely the beak. The trailing edge is curved, and the abdominal edge is straight or slightly concave. The shell is thin, the surface of the shell is smooth and emerald green, the front part is often greenish brown, the growth line is thin, and the front end has convex edges. The inner surface of the shell is porcelain white or bluish blue with pearl luster. The left shell has two hinge teeth, and the right shell has 1. Soft feet, light yellow.