Either way, the Paleozoic Era continued to be dominated by the crinoids and other echinoderms.
无论哪种方式,古生继续由海百合和其他棘皮动物统治。
So, as odd as the starfish body plan seems, something about it was successful -- from their ancient bilateral ancestors, to the radial crinoids with their upward-facing arms, to the predatory, downward-facing starfish.
因此, 尽管海星的体计划看起来很奇怪,但它的某些方面成功的——从它们古老的双侧祖先,到手臂朝上的放射状海百合,再到捕食性的、面朝下的海星。