Eurypterus dekayi Hall 
Page 181 
See plate 19 
1 Hall’s type [Palaeontology of N. Y., v. 3, pl. 82, fig. 1]. Interior view of 
the ventral side of the cephalothorax and of the preabdomen, and 
ventral view of postabdomen and telson. Natural size 
Horizon and locality. Bertie waterlime. Buffalo, N. Y. 
Eurypterus microphthalmus Hall 
Page 192 
2 Carapace, relatively little compressed and showing the lateral eyes and 
ocellar tumescence. Natural size 
Horizon and locality. Manlius limestone. Litchfield, Herkimer co., N. Y. 
3 Type specimen. x 2. [Palaeontology of N. Y.. v. 3, pl. 80A, fig. 7] 
Horizon and locality. Manlius limestone boulder in drift at Cazenovia, 
N.Y. 
4 Large carapace showing broad frontal rim and small lateral eyes. Nat- 
ural size 
5 Large carapace showing somewhat different outline. Natural size 
Horizon and locality. Manlius limestone. Cranes Corners, N. Y. 
6,7 Types of E. eriensis Whitfield. Natural size 
Horizon and locality. Hydraulic (Monroe) limestone of Beach point, 
Put-in-Bay island, Lake Erie, O. 
8 Only specimen with abdomen observed. Shows inner view of carapace 
and ventral view of preabdomen and of three postabdominal segments. 
Natural size 
Horizon and locality. Manlius limestone boulder in drift of Onondaga 
Valley near Syracuse, N. Y. 
g First and second tergites. Natural size 
1o Posterior tergite. Natural size 
Horizon and locality. Manlius limestone. Cranes Corners, Herkimer co., 
N. Y. 
Allfiguresarefrom photographs. Originals of figures1, 2,4,5, 8-10arein 
the State Museum, that of figure 3 is in the American Museum of 
Natural History and those of figures 6 and 7 in Columbia University 
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