Page:The Eurypterida of New York Volume 1.pdf/16

 and the Baltic species now known as   long passed current as.

From 1835 until 1858-59, little was added to our knowledge of the eurypterids except through brief descriptions of a few fragmentary remains from the rocks of Scotland and Russia; then almost simultaneously three fundamental publications appeared, representing the three areas that still today furnish the principal eurypterid faunas. These were Nieszkowski's De Euryptero Remipede [1858], describing elaborately the Baltic species now known as ; Huxley and Salter's classic monograph On the Genus Pterygotus; and James Hall's exhaustive description and beautiful illustration of the eurypterid fauna of the waterlimes of New York, in volume 3, of the Palaeontology of New York [1859]. Nieszkowski's and Hall's papers supplement each other very fully; both described for the first time the whole organization of a eurypterid; they recognized the full number and character of the cephalothoracic appendages exclusive of the chelicerae whose existence was even at this early date intimated by Hall [op. cit. p. 396, footnote]; they established the number of preabdominal and postabdominal segments. They failed, however, in making out the correct number of sternites, Hall recognizing but one (the operculum) and considering the others as ringlike segments, while Nieszkowski (under the guidance of Dr Fr. Schmidt) found out the true platelike character of the sternites, but assumed their number to be six. Huxley and Salter at the same time restored with approximate accuracy the organization of Pterygotus. Both Nieszkowski and Hall recognized the close relationship of the eurypterids with Limulus, while Huxley and Salter adduced other crustaceans for comparison.

Hall described the appendages of the cephalothorax and that of the female operculum in great detail and with his usual accuracy. He