Additional Notes on the Fauna of the Water-Lime Group 

 near Buffalo. 



BY JULIUS POHLMAN. 



i Eurypterus giganteus, n. sp. (Plate II., Fig. i.) 



This is the largest Eurypterus on record. One specimen con- 

 sists of the head and four attached segments of the body, having 

 together a length of ten inches, with a width of nine inches for the 

 widest segment, and of eight and a half inches for the carapace. 

 Accepting the proportions of other Eurypteri this would indicate an 

 animal of a length of thirty inches. There are fragments of three 

 anterior and of both swimming-feet, but their condition is too muti- 

 lated to warrant any attempt at description. The outline and the 

 general surface markings are clearly defined, but the accompanying 

 figure is taken full size, from a young specimen, which shows well 

 the special characteristics. 



It consists of the carapace and part of the first joint of the body. 

 The carapace is semicircular, length to width almost as one to two. 

 The eyes are smooth and reniform, and placed more towards the 

 middle of the head than in any other of the Eurypteri, with the excep- 

 tion of E. microphthalmus, Hall. They are situated mid- way between 

 the anterior and the posterior margins of the carapace, and the dis- 

 tance between them is only a little larger than the distance between 

 the eye and the lateral margin. Between the eyes, and occupying the 

 center of the head, there is a small, smooth circular protuberance. 

 Crust thick and much wrinkled. The surface is covered with pus- 

 tules of varying size which assume a scale-like form near the poste- 

 rior margin of the carapace and on the remaining joint. These 

 markings are like those of E. pustulosis, Hall, but the shape of the 

 carapace and the position of the eyes are so totally different that 

 these two species can be distinguished very readily. Width of cara- 

 pace, three and three-quarter inches; length, two inches. 



Another more fragmentary carapace of the same species, indi- 

 cates an animal of an intermediate size; width of carapace, 5^ inches; 



BUL. BUP. SOC. NAT. SCI. (6) JAN., 1882. 



