They belong to that species of molluscous perforatorswhich excavate holes in the hardest stone; their shell is rounded at bothends, a feature which is not remarked in the common mussel.

• 它们属于穿孔类软体动物，能在最坚硬的岩石中挖洞；它们的外壳两端浑圆，这是一般贻贝所没有的特征。