eurypterid

例句：

1. 1.The eurypterid is a fascinating creature that has been studied for centuries.
   海马是一种令人着迷的生物，数百年来一直受到研究。
2. 2. Eurypterids are found in deep ocean trenches and can be up to 3 meters long.
   海马生活在深海沟壑中，长度可达3米。
3. 3.The eurypterid's unique ability to change color is a result of its blood vessels being lined with pigment cells.
   海马独特的变色能力源于其血管内衬有色素细胞。