PLATE 86 
Pterygotus prolificus nov. 
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1 Very small, well preserved carapace with very prominent lateral eyes. x 3 
2 Small carapace of more roundish outline and submarginal position of 
the eyes. Natural size 
3 Large, well preserved carapace. Type. Natural size 
4 Another large carapace showing the outline of the lateral eyes and the 
filiform border of the head shield. Natural size 
5 A smaller, very roundish carapace, referred with some doubt to this 
Species 
Pterygotus nasutus nov. 
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Type. Well preserved carapace; shows a faint ornamentation. x 2 
7 small carapace, showing relatively greater lateral eyes, somewhat laterally 
compressed 
8 Large carapace, showing the subcircular outline of the lateral eyes. 
Natural size 
g Small, undistorted carapace, showing the original outline. Natural size 
10 Incomplete carapace, showing the border. Natural size 
‘abs 
Disjecta membra of Pterygotus 
t1-15 Patches of integument with beautifully preserved ornamentation, 
characteristic of Pterygotus and exhibiting considerable variation. 
Figures 11-13, X 4; figure 14, K 5 
16 Paddle of swimming foot, resembling that of a Pterygotus. Natural 
size 
17 Fragment of large metastoma, recalling in outline the metastoma of the 
Hughmilleria-Pterygotus group. Natural size 
18 Gnathobase of coxa, probably of swimming leg. Natural size 
19 Portion of chela of a Pterygotus. Natural size 
20 Two segments of swimming leg. Natural size 
Horizon and locality. Lower Siluric: Schenectady shale. The originals 
of figures 1, 5, 6, 11-16 are from the Dettbarn quarry at Schenectady, 
those of figures 2, 7-9 and 17 from Duanesburg, that of figure 3 from 
Rotterdam Junction, those of figures 4 and ro from Rexford, that 
of figure 18 from Central Bridge, that of figure 19 from the Bozen Kill 
west of Altamont. 
All the originals are in the State Museum 
612 
