SYNOPSIS OF GENERA. 



Genus STYLONURUS, Pack. 1850. 



1850. Stylonurus, Page. Advanced Text-1 k of Geology. 



1857. Eurypterus, Salter. Edinb. New Phil. Jonrn. 



1859. Stylo7iurus, Page. Advanced Text-1 k of Geology, 2d ed. 



1859. Eurypterus | i>,aiim), Salter. Quart. Joura. Geol. Society. 



1859. Eurypterus, Salter. In Mui-ehison's Siluria, 3d ed. 



1864. Stylonurus, Woodward. British Assoc. Rept. 



1867. Stylonurus. Murchison's Siluiia, 4th ed. 



1881. Equisetides, Dawson. (?) Quart. Journ. Geol. Soc, vol. xxwii. 



1882. Stylonurus, Martin. Trans. N. Y. Acad, of Sciei 3. 



1S83. Dolirlioct -phalli. Claypolb. Proc. Auier Philos. Soc. 



1883. Stylonurus, Hall. Thirty-sixth Rept. N V. State .Mas. Nat. Hist. 



Diagnosis. Body in general propor- 

 tions similar to Eurypterus. Cephalon 

 sub-quadrate or sub-pentagonal in 

 outline. Eyes large, circular and 

 approximate, sometimes surrounded 

 by conspicuous orbital ridges. Ocelli 

 situated at the posterior extremity of 

 a median ridge, passing between the 

 eyes. Surface coarsely squamose. 

 Cephalic appendages in five (?) pairs, 

 the last of which are produced nearly 

 to the extremity of the telson. Seg- 

 ments of the Abdomen as far as known, 

 similar to those in general features 

 of Eurypterus. Those of the post- 

 abdomen each bear a pair of lateral, 

 detachable processes or epimera. Cau- 

 dal spine long and slender or sub- 

 clavate. 



Restoration ol Stylonurus Logani, ai ng to Woodward. 



