Page:The Eurypterida of New York Volume 1.pdf/296

 reach their largest size on the frontal mound and cheeks and extend over the whole carapace, including the eye mounds, in uniform density.

The abdomen is slender. It expands gradually to the fourth segment whence it contracts again as gradually to the long and slender postabdomen. The greatest width is probably about one fourth greater than that of the carapace. The preabdomen is longer by one third than the carapace, and the postabdomen is but little longer than the preabdomen. The tergites are short plates with nearly straight anterior and posterior margins, while the sternites exhibit strongly curved posterior margins, the middle being strongly concave and the postlateral angles well rounded and produced backward. Traces of a marginal line of tubercles on the tergites have been observed and it is possible that the whole surface was tuberculate.

The telson has not been observed in position, but it is quite probable that a slender spine, found in association with these remains, belongs to this species since it fully corresponds to the form of the postabdomen.

Appendages. The chelicerae and first pair of legs have not been seen. Of the second pair but four segments of the specimen could be exposed without destroying the following legs, and of the third pair also a portion of a fifth segment. These exposed portions show that the legs were long and slender, the third still somewhat surpassing the second in length; thus the second to fourth legs continuously increase in length backward. The fourth and fifth segments, and presumably the following ones, are furnished with a series of straight, slender paired spines, about 6–9 pairs on each segment. The fourth and fifth pairs of long legs were not of equal size, but the fourth shorter by one eighth. The latter, fully reflexed, would reach the last postabdominal segment and the fifth leg the telson. The coxae of these legs are not exposed; the first and second segments, however, are partly seen and can be recognized as consisting of short rings; the third is somewhat longer, while the fourth is the longest and broadest of all. It is two and one half times as long as the third. The sixth is again shorter by one third while the seventh and eighth are distinguished by again increasing in length and decreasing notably in width. The