NIAGARA FALLS AND VICINITY 229 



progressively increasing in length backward, the anterior pair with 

 pincers or chelae; second, third and fourth pair six to seven-jointed, 

 and covered with fine spines; fifth pair eight-jointed; posterior pair 

 consisting of eight segments, large and powerful, with a large, sub- 

 quadrate basal joint in each, and a broad terminal " paddle ". An- 

 terior six abdominal segments occupying together about one fourth 

 of the entire body length, short, broad and nearly uniform in shape. 

 Succeeding six segments are ring-like, progressively decreasing in 

 diameter, thus causing a tapering of the body. Telson long and 

 slender. 



Eurypterus lacustris Harlan (Hall. 1859. Pal. N. Y. 3:407*, 

 pi. 81, 81A, 81B, 83B) 



Distinguishing characters. Animal stout; anterior portion of the 

 abdomen very broad, abruptly tapering beyond the sixth segment; 

 penultimate segment quadrate, without lateral flanges. 



Very abundant in the Waterlime of North Buffalo. 



Eurypterus remipes De Kay (Plate 18) (Hall. 1859. Pal. 

 X. Y. 3:404*, pi. 80, 80A, 83B) 



Distinguishing cliaractcrs. Animal small, with lateral body mar- 

 gins making broad outward curves and tapering very gradually 

 backward. Penultimate segment slightly if at all flanged. 



Occasionally in the Waterlime of North Buffalo. 



Eurypterus pustulosus Hall (1859. P^- N. Y. 3:413*, pi. 83B), 

 Eurypterus giganteus Pohlman (Buffalo soc. not. sci. Bui. 



Distinguishing characters. Cephalothorax large, short and very 

 broad: eyes on the median transverse line; surface strongly pus- 

 tulose. 



A single specimen has been recorded from the Waterlime of 

 North Buffalo. 



Eurypterus robustus Hall, Eurypterus 1 a c u s t i s var. r o - 

 bustus Hall (1859. Pal. N. Y. 3:410*, pi. 81C) 



Distinguishing characters. Like E. lacustris, but larger and 

 more robust, and proportionately narrower over the anterior ab- 

 dominal region. 



Common in the Waterlime at North Buffalo. 



