The Starfish is one of the most curious creatures in the sea.

    The Starfish is one of the most curious creatures in the sea. It is called an " Echinoderm", which means it is spiny-skinned. In the middle of their bodies on both the top and bottom, are button-shaped disks. Through these disks they draw in or expel sea water. The disks on the underside act as mouths. Their eyes are at the tips of their arms and are protected by a circle of spines. Along the underside of their arms are grooves, and along these are arranged little tubelike sucker feet. These are used both for moving about and as organs of smell.

    One amazing thing Starfish can do is open an Oyster. They do this by attaching their sucking disks to either half of the oyster shell and pulling until the shell eventually opens.

    Coelenterata are a group of small animals including sea anemones and corals. Most of them live in the sea and have arms covered with stinging cells. They feed on plankton.

    海星是海洋中最古怪的动物之一。它是一种棘皮类动物，身上皮肤长满刺。在它们身体的中间，上下都有纽扣状的吸盘。它们通过这些吸盘吸水排水。内侧的吸盘是嘴。它们的眼睛位于手臂的顶端，被一圈骨刺保护着。沿着手臂内侧长有一些凹槽，里面长有吸管状的吸足。这些是吸足既可以用来移动，也是嗅觉器官。

    奇特的是海星能够打开牡蛎。它们把吸足贴到牡蛎的两片壳上，用力的拉，直到打开为止。

    腔肠动物体型都比较小，包括海葵和珊瑚虫。它们中的大多数生活在海洋中，手臂上铺盖着蛰刺细胞，以浮游生物为食。