sentences:  Despite its fragmentary nature, the quadrangular (square) shape of the carapace and the eyes placed at its corners allowed zoologist and paleontologist Malcolm Laurie to place it within "Slimonia" when describing it in 1899.The size of the carapace suggests that the species would have grown to 12 cm (5 in) in length.Another species, "S. stylops", was first considered a species of "Pterygotus" when described by John William Salter in 1859, and the highly fragmentary nature of the known fossils make a precise identification difficult and problematic.