translation.en: It had the central fluid, it had the surrounding wall, and the reinforcing fibers in the wall were arranged in crossed helices around the long axis of the skeleton.
translation.zh: 它的中央有液体 周围有外壁 外壁中有强化纤维 这些纤维以交叉螺旋的形式 排列在骨骼的长轴上