Page:The Eurypterida of New York Volume 1.pdf/399

 "There are oval bodies," he says, "which correspond to the lung sacs of the scorpions," adding, "Nothing can be observed of openings of these sacs, namely stigmata, to the outside." This inference is due to a deceptive feature of the photograph, in which fragments of the test of the tergites and slight folds give the appearance of oval depressions in the underside of the preabdominal segments.

The tergites are of relatively greater width than those of Palaeophonus, especially. The first is the shortest and the tergites gradually grow in length backward. The anterior and posterior margins are nearly straight, the lateral margins not well seen, owing to the crumbling of the edges. It is obvious, however, that they did not diverge forward as in Palaeophonus or were entirely rounded off as in Eoscorpius but diverged backward to the fourth, which is the widest, then again contracting. The first seems to have been rounded at the posterior angles. The anterior edge of the tergites possesses a transverse, forward sloping, smooth, articulating band which is a rather prominent feature though but faintly seen in the photograph. It does not, however, follow the lateral edges as figured by Whitfield, nor does it exhibit the raised transverse line appearing in the original figure of the species.

Postabdomen. The first metasomatic or postabdominal segment has the form of a truncate cone, as in other scorpions. Of the narrow tail four segments are seen in an impression only. These also have led to some discussion, as Whitfield, in consequence of his conception of the presence of ventral preabdominal plates, inferred that the impression is that of the ventral side of the tail. This side shows only two longitudinal ridges like the dorsal side in other scorpions, and hence the conclusion was reached that the "bending of the tail was downward, not upward, over the back." Against this Thorell has urged that probably the tail, which is detached, has been turned upside down and that now the inside of the dorsal side is seen in the impression. The oblique position of the frontal margin of the tail to the posterior margin of the first postabdominal segment, and the lateral position of the two carinae of the first tail segment serve to show that the tail is out of its original position, and that therefore no