produced into a relatively large triangle in the middle line. The eyes were large (between one third and one fourth the length of the carapace), reniform in outline and situated on the anterior half of the carapace, separated by about their own length from the outer margin. The preabdomen is so broad that its length is to its width almost as 2 : 3. The broadest part is in the region of the fourth tergite or third sternite. On account of the complete flattening of the specimens, both the tergites and sternites appear only as ill defined bands, the overlap, and consequently the true length, of which can not be determined. So much, however, is certain that they were rather short and wide, about seven times as wide as long. Their doublures can not be satisfactorily seen. The postabdominal segments are better shown and their broad posterior doublures well observed in all specimens. The postabdomen is relatively short and broad, it reaches not more than one third the length of the body while in the typical species of Eurypterus it amounts to one half of that length. It tapers gradually to not quite one third its anterior width. The postabdominal segments are short, the length of the penultimate segment to its width having the proportion of 2 : 3. The ultimate postabdominal segment is furnished with two short blunt lobes of the postlateral angles. The telson, corresponding to the rest of the body, is short and strong, rapidly tapering to the distal extremity. Its length was apparently only about one fourth or one fifth of the whole body.
Appendages. The limbs indicate that this species was a better walker than swimmer, for while the walking legs were strong and well developed, the swimming legs are rather slender and furnished with but small paddles. These paddles also seem to have ended in a spine although the evidence on this point is not conclusive, only a single indication of the spine having been seen. The details of the walking legs are not very distinct. The last pair, which typically in Eurypterus is comparatively slender, is here short when compared to the great width of the carapace, but somewhat broad jointed. The swimming legs are long in comparison with the short body. When turned back they reach to the posterior edge of the preabdomen.
