which may correspond to the finely haired cushion which Holm observed on the coxa of the first walking leg and which he considers as possibly corresponding to the epicoxite of the following legs. The posterior portion of the coxa is partly lost as shown by the broken edge. The next segment is short and broad, about as wide as long, while the third, the longest of the series, is twice as long as wide. The following segments decrease rapidly in length and at a lesser rate in width. The terminal segment is spiniform. The spines, two of which are borne on each segment, save the first two and the last, increase in size regularly to the distal spines which are the longest.
 Figure 56 Diagram of ventral view of right swimming leg of Eusarcus. m, metastoma; the figures indicate the segments |
The detached walking leg consists of seven segments. Its short and thick form and the composition of seven segments indicate that it was one of the first pair of walking legs. None of the following legs have been seen entirely free, but the combined evidence of our specimens leads to the inference that they consisted of eight segments each, as in Eurypterus.
The swimming leg, corresponding to the plump form of the animal, is of massive proportions and furnished with a large paddle. The seventh and eighth segments forming the latter, are greatly lengthened and broadened and the segments connecting this paddle with the coxa are shortened and swollen for the reception of powerful muscles, held together by strongly interlocking articulations and, as their frequent plastic preservation shows, were covered by a thick periderm. Compared with the swimming leg of the species of Eurypterus this leg makes the impression of a much stronger,
