Palaeocopida

例句：

1. 1. The fossils found in the cave are part of the Palaeocopida.
   洞穴中发现的化石是古生动物亚纲的一部分。
2. 2.Palaeocopida is a group of ancient animals that lived over 500 million years ago.
   古生动物亚纲是一类生活在5亿多年前的古老动物。
3. 3.The discovery of these fossils has helped scientists understand the evolution of life on Earth.
   这些化石的发现帮助科学家理解了地球上生命的进化过程。