Jan Nieszkowski's "De Euryptero Remipede" (1858) featured an extensive description of "Eurypterus fischeri" (now seen as synonymous with another species of "Eurypterus", "E. tetragonophthalmus"), which, along with the monograph "On the Genus Pterygotus" by Thomas Henry Huxley and John William Salter, and an exhaustive description of the various eurypterids of New York in Volume 3 of the "Palaeontology of New York" (1859) by James Hall, contributed massively to the understanding of eurypterid diversity and biology. These publications were the first to fully describe the whole anatomy of eurypterids, recognizing the full number of prosomal appendages and the number of preabdominal and postabdominal segments. Both Nieszkowski and Hall recognized that the eurypterids were closely related to modern chelicerates, such as horseshoe crabs.