Page:The Habitat of the Eurypterida.djvu/35

 eurypterids, which are recognized in our formations. (Pterygotus and Eurypterus).

". . . . Far from finding individuals complete and well preserved, it will prove difficult to add any new facts of importance to those already published on the organization of the species of this type.

"That advantage is not reserved for us, for the Silurian basin of Bohemia, so favored in all other respects, is relatively poor in fossils of the genus Pterygotus, not only because of their great rarity, but also because of the reduction of the specimens to little fragments. Since almost all of the remains are found in the large horizon of the Cephalopods, that is, in our limestone band e 2, it seems to us that one may attribute the almost total disappearance of these gigantic Crustacea to the voracity of these molluscs, against whom they were forced to maintain the struggle for existence." (13, 556).

We need not consider seriously this interpretation of the fragmental character of the eurypterid remains as they can be interpreted in another manner (see p. 199).

Semper (261) has recently done some work in the region and has revised and added to Barrande's original species. In e1 β at Podol Dvorce, near Prague, he has collected a few fragments to which he has given the name Pterygotus barrandei of which there are also some fragments at Dlouhá hora, in horizon e2. A few endognathites from the former locality have been described as P. beraunensis Semper, since they come from near Beraun. Some fragments of a swimming foot are also described by Semper from e2, as P. blahai, in a thinly laminated limestone rich in Orthoceras which occurs at Viŝňovka near Lochhov. Of all the species found in Bohemia the best one is a fragmentary individual showing the head with the first eight somites attached, and a few separate fragments, these constituting the species Eurypterus acrocephalus Semper from horizon e1, at Dvorce. From these various occurrences it is apparent that the eurypterids, though represented by a large number of species in the beds of Wenlock or Niagaran age of Bohemia, are found only rarely and in a most fragmentary condition, although the large marine fauna occurring in the same horizon is one of the largest and most perfect that is known, forming the basis for Barrande's ponderous work on the Système Silurienne in which many volumes are devoted to the description and figuring of the marine fossils, while a very little space suffices for the meagre eurypterid fauna. Barrande notices in a paper on the