| 释义 |
〔periostracum〕The hard chitinous outer covering of the shell of many mollusks, especially freshwater ones, that protects the shell from the erosive action of water.角质层：许多软体动物，尤指淡水软体动物身体硬壳外包的一层物质，用以防止壳受水的侵蚀作用〔peneplain〕A nearly flat land surface representing an advanced stage of erosion.准平原：一种因晚期侵蚀作用而形成的近似平坦的地面〔wasting〕the wasting process of erosion.侵蚀作用的逐渐腐朽过程 |