1·Though they are commonly called starfish, these animals are not fish at all. They are echinoderms, closely related to sea urchins.
虽然它们通常被称为海星，这些动物不是鱼，它们是棘皮动物，与海胆密切相关。
2·Popularlyknown as starfish, sea stars are actually echinoderms, closely relatedto sea urchins and sand dollars.
海星实际上是棘皮动物，和海胆和饼海胆是近亲。
3·Echinoderms are now considered as a biological and geological model that underlies researches of primary importance.
棘皮动物现在被认为是生物和地质模型，头等重要的基础研究。