It is a class of small crustaceans, belonging to the gill-footed class, dorsal armor, now known about 15 species of horseshoe crab worms are freshwater horseshoe crab worms, inhabited in lakes and ponds, mainly distributed in Europe and North America, China has only found one species of horseshoe crab worms in abundance. The large dorsal shell of the horseshoe crab is oval, and the abdomen is slender, soft and flexible. The long tail is forked. The body is about 100 millimeters long, divided into about 40 segments, with some leaf-like appendages. Some limbs are as many as 70 pairs.

The three-eyed dinosaur shrimp is so vigorous that it has existed for 200 million years. This creature, which has existed on Earth since 200 million years ago, has recently been used by many Japanese farmers as a pesticide substitute for growing rice, because the three-eyed dinosaur shrimp can remove weeds from paddy fields and make rice grow better, which is very interesting.