and the telson is in both specimens narrower than in P. macrophthalmus, a difference which is surely in part and perhaps wholly due to preservation, the thin telsons being somewhat laterally compressed.
On account of the scarcity of the material we do not know to what extent these differences are expressions of different growth stages, but it is quite obvious that P. cobbi as represented by these specimens, was remarkably similar in all its features, save the pincers, to P. buffaloensis and P. macrophthalmus.
Judging from the fragmentary pincers of the specimen figured by Pohlman [1883, pl. 3, fig. 3] as P. buffaloensis, we surmise that this also belongs to P. cobbi.
Horizon and locality. Bertie waterlime, Schooley's farm, Litchfield, Herkimer co., N. Y.
 Fig. 120-21 Pterygotus cobbi var. juvenis nov. Fig. 120 Dorsal aspect. Fig. 121 Ventral aspect. Both somewhat laterally compressed. Natural size |
