Noun:
-
shallow-water echinoderms having soft bodies enclosed in thin spiny globular shells
- A fine,sharp projection,as a spine of a sea urchin or a crystal.
针状物精细尖锐的突出物，如海胆的脊椎骨或水晶球。
- The hard outer shell of sea urchins are commonly called tests.
海胆的坚硬外壳通常被称为甲壳。
