- n Eurypterida extinct aquatic arthropods of the Paleozoic
Century Dictionary and Cyclopedia
- eurypterida A group of extinct Silurian Crustacea, sometimes included in Merostomata, sometimes made a distinct order. Some of them attained a large size, and in many respects resembled Limulus, while in others they approached the Copepoda. An anterior cephalothorax, bearing eyes and limbs, is succeeded by 12 or more free somites, the body then terminating in a telson. Some of the anterior limbs may be chelate, as in Pterygotus, and the terminal joints of the last pair are usually expanded and paddle-like. Also Eurypterina.