THE EURYPTERIDA OF NEW YORK 323 
joint seven, as restored to its natural position, would be 12.5 centimeters, 
exclusive of the basal joint ataa. The long spines of the joints 3 and 4 
are 5 centimeters in length. 
The joint marked (1) is broad and short with a rounded depression at 
the center of its inner margin. ‘There is no evidence of the attachment 
of the long spines that are articulated to the posterior side of the succeeding 
joints. From the form of the joint and the presence of broken fragments 
of the test in the matrix at aa it is probable that it is the second joint of 
the appendage and that the first or basal joint is broken up. The joint 
(2) is large, elongate, rudely subtriangular, the long anterior margin curving 
around to meet the nearly straight posterior margin at its inner end. The 
latter margin has nine long curved spines articulated to it while the three 
following joints (3, 4 and 5) have but three each on their posterior margins. 
These joints (3, 4, 5), are more or less quadrangular in outline, (3) and (4) 
being transverse and (5) a little elongate. The spines of (3) and (4) are 
the longest of any attached to the appendage. Beyond (5) traces of another 
joint are shown (6), and another is indicated by the position of the three 
curved spines beyond those of (6). These two latter joints were crushed 
by the forcing back of the long terminal joint (7), the inner end of which 
is seen beneath the center of the joint (4). This joint or terminal spine 
is slender, slightly curved backward, and marked by a slight median ridge 
and longitudinal striae. The surface of the joint (1) and the anterior 
portions of (2) and (3) show the scalelike markings observed on the frag- 
ment of the thoracic segment. If there were but one joint beyond the 
transverse joint (1), 1. e., the basal, the entire appendage would have had 
nine joints, if our interpretation of the crushed joints is correct. . 
The long curved spines (s, s, s), are a very curious feature of the ap- 
pendage and the most marked character of the genus and species. They 
are articulated to the posterior margin of the joints, as the latter rest flat- 
tened out in the slate or shale, and there is no evidence but that they form 
a single series as shown in the specimen and in the drawing, figure 2. Each 
spine is constricted a little near its base, forming a rounded end or point 
of articulation; from this well out toward their pointed termination they — 
retain an average width curving gently backward and inward. They 
appear to have been flattened when in a natural condition, and formed. 
of a thin test which is rather strongly striated. 
Horizon and locality. Utica slate, Holland Patent, Oneida co., N. Y. 
Remarks. The great width of the earlier joints of the leg and the 
very rapid tapering of the limb suggest that it was a first endognathite 
and that it consisted of eight segments, counting the terminal spine. It is 
