1) Animal order 2) Order eurypterida 
Eurypterida meaning wide wing) are extinct carnivorous marine arthropods (segmented invertebrates with a chitinous exoskeleton and jointed legs), also called sea scorpions. These hunters had a scorpion-like stinger which may have contained poison, 3 pairs of jointed legs, 2 clawed arms, and strong jaws. Some had two paddles for swimming. They may h...
[n] - extinct aquatic arthropods of the Paleozoic
order Eurypterida noun extinct aquatic arthropods of the Paleozoic