The mussel, also known as qingkou, is a bivalve mollusk with a dark brown shell that lives on a beach rock. It is distributed along the yellow sea and the bohai sea. The shell is wedged, the front end is thin and the back end is wide and round. The shell is 6 ~ 8 cm long, and the shell is less than 2 times that of the shell. Thin shell. The front-end of the shell near the shell. The two shells are the same, the left and right sides are symmetrical, the shell face is purple and black, with the luster, the growth grain is fine and obvious, from the top to ring growth.