. The Eurypterida of New York. Eurypterida; Paleontology. THE EURYPTERIDA OF NEW YORK 221 of the genus and in this evidence of waning racial characters it invites special recognition. The Pennsylvania species to which we have referred are E. mansfieldi C. E. Hall, E. pennsylvanicus C. E. Hall, E. stylus J. Hall and E. approximatus Hall & Clarke.' These species, together with E. (Anthraconectes) mazon- e n s i s are distinguished from Eurypterus proper by the following features: (i) the character of the spines of the endognathites,^ seen in E . mans- fieldi, in E. mazonensis and E. stylus,^
. The Eurypterida of New York. Eurypterida; Paleontology. THE EURYPTERIDA OF NEW YORK 221 of the genus and in this evidence of waning racial characters it invites special recognition. The Pennsylvania species to which we have referred are E. mansfieldi C. E. Hall, E. pennsylvanicus C. E. Hall, E. stylus J. Hall and E. approximatus Hall & Clarke.' These species, together with E. (Anthraconectes) mazon- e n s i s are distinguished from Eurypterus proper by the following features: (i) the character of the spines of the endognathites,^ seen in E . mans- fieldi, in E. mazonensis and E. stylus,^ (2) the develop- ment of the scales into mucros, giving the greater portion of the surface a spinous appearance. This tendency to spinosity, especially of the posterior margins of the abdominal somites is also present in British Carbonic forms, as is amply evidenced by E. scouleri Woodward^ with its long pointed scales, E. (?) stevensoni R. Etheridge jr [Geol. Soc. Lond. Quar. Jour. 1877. 33:223] in which the surface is covered with long blimt spines and scales, giving it the appearance of a mass of congealed drops, Figure 48 e u r y p - while in E. scabrosus H. Woodward' the scales lll'tl-^'IJ^-V' have become prominent wartlike tubercles, inter- spersed with disklike bodies which proved to be ''calculi'' or bodies of globular calcite formed inside the integument. All these excrescences are distinctly phylogerontic and seem to indicate that. spines aixd. scales. (From Etheridge) ^ The first two are described in the Proceedings of American Philosophical Society, volume 7, 1877, and Second Geological Survey of Pennsylvania, Report of Progress, PPP, 1884, page 31 et seq. E . stylus is described in the last named pubhcation and E. approximatus in the Palaeontology of New York, volume 7, 1888, explanation of plate 27, figure 6. E. potens Hall is not described and the figures [Penn. Rep't, pi. 4, fig. 9, 10] indicate that it is based on unrecognizable fragments. ^ See Appendix. ^In
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