240 NEW YORK STATE MUSEUM 
but less active and movable organ. The coxa has not been seen entirely 
free. Enough, however, is shown to indicate that it is of a rhomboidal 
outline, like that of Eurypterus, differing in that it is relatively higher and 
shorter [pl. 32]. The gnathobase is not preserved in the specimen cited. 
The second segment is not short and ringlike as in Eurypterus, but cup- 
shaped, widening rapidly distally. It is connected by the narrow ringlike 
or wedge-shaped third segment to the ringlike fourth segment. In an old’ 
Figure 57 Eusarcus scorpionis Grote & Pitt. Portion of dorsal view of left swimming 
leg. Natural size. Original in State Museum 
individual [text fig. 57] the three segments mentioned form a powerful 
spherical part of the leg. The fifth segment is ringlike on the under- 
side of the limb, widens out and is extended anteriorly on the upper 
side. Near the center of the flaring upper portion of this segment the 
next, sixth, segment is inserted. This appears from both sides as a tri- 
angular, or originally rather conical body, the distal basal surface of which 
is deeply emarginate on the posterior side and extended on the anterior, 
so as to fit into the deeply emarginate basal portion of the seventh joint. 
_ The latter is by far the broadest segment of the limb and nearly as long as 
