Waeringopterus (Pterygotus) prolificus nov. Page 382 1 Very small, well preserved carapace with very prominent lateral eyes. × 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. Page 382 6 Type. Well preserved carapace; shows a faint ornamentation. × 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 9 Small, undistorted carapace, showing the original outline. Natural size 10 Incomplete carapace, showing the border. Natural size

Disjecta membra of Pterygotus 11–15 Patches of integument with beautifully preserved ornamentation, characteristic of Pterygotus and exhibiting considerable variation. Figures 11–13, × 4; figure 14, × 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 10 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