Any of numerous radially symmetrical marine invertebrates of the phylum Echinodermata,which includes the starfishes,sea urchins,and sea cucumbers,having an internal calcareous skeleton and often covered with spines.
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美
- 棘皮动物,任一种属于棘皮动物门的许多呈辐射对称状的海生无脊椎动物,包括海盘车、海胆和海参,内部骨架含钙,常覆盖有棘针。