THE EURYPTERIDA OF NEW YORK 149 
tacean features in the ontogenies of Limulus and the scorpion, it becomes 
manifest that the inference of the derivation of these classes from arthro- 
pods more primitive than the Crustaceans, seems well founded. 
Through the suggestive investigations of Professor Patten, published 
in his paper On the Origin of Vertebrates from Arachnids and the ingenious 
speculations of Dr Gaskell as to the origin of the vertebrates from some 
Limuluslike ancestor, the eurypterids have gained increased interest and 
some notoriety as possible ancestors of the earliest vertebrates. 
VII 
SYNOPTIC TABLE OF THE NORTH AMERICAN EURYPTERIDA 
Those marked by an asterisk are found in New York State. 
_ Class ARACHNIDA 
Subclass MEROSToMATA (Dana) Woodward 
Order FURYPTERIDA Burmeister 
Family suryYPTeERIDAE Burmeister 
Genus pouicnorTrerus Hall 
Type: *Dolichopterus macrochirus Hall 
*D). frankfortensis nov. 
*D). latifrons nov. - 
*D. otisius Clarke 
*D. siluriceps nov. 
*D. stylonuroides nov. 
*D. testudineus nov. 
Genus secanocnataus Walcott 
Type: *Echinognathus clevelandi Walcott 
Genus ruryrterus DeKay 
Type: *Eurypterus remipes DeKay 
*E, approximatus Hall & Clarke 
*E. dekayi, Hall 
*H. lacustris Hall 
