I4 NEW YORK STATE MUSEUM 
books and the Baltic species now known as E. fischeri long passed 
current as E. remipes. 
From 1835 until 18s8-s9, 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 simul- 
taneously three fundamental publications appeared, representing the three 
areas that still today furnish the principal eurypterid faunas. . T hese 
were Nieszkowski’s De Euryptero Remipede [1858], describing elabo- 
rately the Baltic species now knownasE. fischeri; HuxleyandSalter’s 
classic monograph On the Genus Pterygotus; and James Hall’s exhaustive 
description and beautiful illustration of the eurypterid fauna of the water- 
limes of New York, in volume 3, of the Palaeontology of New York [18509]. 
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. czt. 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 
! Hall submitted his collection to Professor Agassiz who gave “his opinion most 
unequivocally that the Eurypteri are closely related to Limulus, belonging even to 
the same order.”’ 
