146 C. E. Beecher — Restoration of Stylonurus Lacoamis. 



Historical. 



The first specimen found in America that can be referred to 

 the genus Stylonurus was collected by the writer about 1870, 

 and loaned to Professor James Hall. It remained in his hands 

 unnoticed until 1884, when he described it as Exiryjpterus 

 Beecheri.* The specimen preserves the abdomen and portions 

 of two of the large posterior limbs. No species of Eurypterus 

 known possessed such greatly elongated limb joints, and there 

 seems to be no good reason for not referring it to Stylonurus, 

 in which this is a normal character. The specimen of Stylo- 

 nurus Beeoheri is uncompressed, and apparently retains the 

 proportions of form and convexity as in life. On this account, 

 it was of considerable importance in the restoration of the 

 larger species. 



In 1882, Hall was furnished with a plaster cast of the cara- 

 pace of a large arthropod, by Dr. Cook, then State Geologist 

 of New Jersey. The original specimen was from the Catskill 

 group at Andes, Delaware County, New York, and had been 

 sent to the museum at Rutgers College, New Brunswick, New 

 Jersey. Prof. D. S. Martin 9 made the first reference to this 

 species in some remarks on " A New Eurypterid from the 

 Catskill Group," before the New York Academy of Sciences, 

 October 16, 1882, an abstract of this note appearing in the 

 transactions of the same society some time after June, 1883. 

 In this abstract, the species is neither described nor figured, 

 and Hall is not mentioned in any connection. Martin states 

 that he saw the specimen (=cast sent to Hall) in the State 

 Museum at Albany, and it bore the name Stylomurus excelsior 

 (evidently a misprint for Stylonurus). 



The next reference to this form in point of time, and the 

 first publication of a generic and specific name accompanied 

 with a description and accurate illustration, was given by E. 

 W. Claypole, 1 in a paper read before the American Phil- 

 osophical Society, September 21, 1883, under the title "Note 

 on a large Crustacean from the Catskill Group of Pennsyl- 

 vania." It is stated on the signature containing this paper 

 that it was printed November 2, 1883. Claypole's description 

 was based upon a second specimen found in Wyoming County, 

 Pennsylvania, which preserves about three-fourths of the ceph- 

 alothorax, and belonged to the collection of R. D. Lacoe of 

 Pittston. This was given the name Dolichocephala Lacoana, 

 and rightly classified with the Merostomata. It therefore 

 appears that, up to this time, the name Stylonurus excelsior 

 was simply nomen nudum, and as such cannot be recognized 

 as valid. 



In 1884, Hall 3 published his description and figure of the 



