THE EURYPTERIDA OF NEW YORK 239 
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 cor- 
responding 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 broad- 
ened 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, 
