Hexactinellida

例句：

1. 1.Hexactinellida is a group of animals with six legs.
   六足纲是一种有六条腿的动物。
2. 2.The discovery of Hexactinellida has revolutionized our understanding of life on Earth.
   六足纲的发现已经改变了我们对地球上生命的认识。
3. 3. Hexactinellida are found in various ecosystems around the world.
   六足纲分布在世界各地的各种生态系统中。