THE EURYPTERIDA OF NEW YORK 17 
Carbonic age from the American continent had been made in 1868 by 
Meek and Worthen who described Eurypterus mazonensis 
from the Coal Measures of Illinois, erecting for it the subgenus Anthra- 
conectes, and in 1877 C. E. Hall described two species (E. penn- 
sylvanicus and E. mansfieldi) from the Coal Measures of 
Pennsylvania. James Hall noted four species from the Carbonic of that 
State, adding two types to those before known, and he described besides a 
new form from the Chemung groupof Warren, Pa. (E. beecheri) 
which Beecher later determined to be a Stylonurus. 
_ Considerable progress in the understanding of the organization of 
the eurypterids and especially of the genera Eurypterus and Pterygotus, 
was made by Fr. Schmidt’s admirable investigations entitled Dvze 
Crustaceenfauna der Eurypterenschichten von Rootztkull auf Oesel pub- 
lished in 1883. Nieszkowski’s work had already been done under Dr 
Schmidt’s supervision and Schmidt now carried out a very detailed examina- 
tion of the remains of Eurypterus fischeri and Pterygotus 
osiliensis. He was thereby enabled to correct many details of Hall's 
and Nieszkowski’s descriptions of the appendages; to show the existence of 
five ‘‘ Blattfusse’’ or sternites open on the ventral side, as in Limulus; 
to recognize sexual differences in the opercular appendages; to establish 
the correct number of walking legs in Pterygotus (8, while Woodward 
assumed 6), and the form and position of the epistoma. 
In 1884 Whiteaves made known an Eurypterus (E. boylei) from 
the Guelph limestone of Canada, and in 1888 Matthew described as 
Eurypterella ornata, a peculiar Devonic organism that is 
referred by him to this group. 
In this year, 1888, also appeared volume 7 of the Palaeontology 
of New York by Hall and Clarke. This volume supplements the descrip- 
tion of the Siluric eurypterids in volume 3, by bringing together 
the remaining merostomes from the State of New York and the adjoining 
regions. It contains a full size drawing of Hall's type of the 
famous carapace of Stylonurus excelsior and gives an 
