mermithid

例句：

1. 1. The mermithid was a rare and fascinating creature.
   这个水生爬行动物是罕见的，非常迷人。
2. 2. The mermithid is found in the oceans around the world.
   这种水生爬行动物在世界各大洋中都有分布。
3. 3. The mermithid has been studied for its unique adaptations to life in water.
   这种水生爬行动物因其独特的适应水生生活的能力而受到研究。