英语语法分析

Eurypterid: any of various large segmented aquatic arthropods of the order eurypterida that existed from the ordovician period to the Permian period.

(古生)板足鲎目的：一种巨大的、有节的，属于板足鲎目的水生节肢动物，生存于奥陶纪到二叠纪时期。