Wikipedia
Euproops
Euproops is an extinct genus of xiphosuran, related to the modern horseshoe crab. It lived in the Carboniferous.
The Treatise on Invertebrate Paleontology describes Euproopidae as "small forms with wedge-shaped cardiac lobe bordered by distinct axial furrows, abdominal shield with annulated axis bearing a high boss on last segment." The same source describes Euproops as follows. "Prosoma with flat genal spines and carinate opthamalic spines; cardiopthamalic region with or without intercardiopthamalic area; abdomen with raised pleural ridges that cross flattened rim and are prolonged as marginal spines; annulated axis with knob on 1st and 3rd segments and elevated boss or short spine on hindmost segment; telson long. "