That's because chelicerates have blood that has a salinity similar to that of sea water.

那是因为螯足动物的血液的盐度与海水的盐度相似。

And in the seas there are the sea spiders and the primordial-looking horseshoe crabs -- living reminders of the watery origin of the chelicerates and the reign of the sea scorpions.

海洋中有海蜘蛛和长相原始的马蹄蟹——活生生地提醒着螯虾的水源起源和海蝎的统治。