Tetrarca boucardi Jousseaume, 1894Shell elongate squarish, inflated, 17.5 mm in height, 32.1 mm in length and 16.9 mm in breadth; anterior side short and rounded, posterior elongated, sides an- gulated at the upper; umbos remote, a keel running from umbo to posterior ventral corner, ventral margin with a large gape for the passage of the byssus; area of ligament very wide, with many diamond-shape grooves; surface with numerous radial riblets and concentric lines; white, covered with a thin, rather bristly brown epidermis. Distribution: Along the coasts of China; Japan; Korea. Ecology: Found attached to rocks or gravels by byssus from intertidal zone down to about 68 m deep, very common in the North China coasts.