REPORT OP THE STATE PALEONTOLOGIST 1902 1107 



spiniferous. The terminal is about equal in length to the spines 

 and, like the terminal appendage in the other group, is clawlike. 

 This arm, judging from the shortness of the joints and the broad- 

 ening at the articulations, probably corresponds to the second 

 described from the other group. The joints of the other arm 

 appear to correspond to part of joints two and three of the first 

 of that group. 



Associated with this last, and lying partially beneath its 

 larger end, is a fragment of test which is ornamented by sharp, 

 triangular scales differing from anj^thing found on the other 

 eurypterids herein described. However, it is not certain that 

 this had any connection with this arm. Aside from this possi- 

 bility, neither the appendages nor the sternite show any signs 

 of ornamentation. 



The most noticeable features revealed by these specimens 

 are: the robustness and the great difference in size of the 

 several pairs of endognathites; on the anterior three of these 

 the arrangement in pairs of the posterior spines, which, on the 

 first two, are noticeable for their shortness and lanceolate 

 form, and on the third for their length and curvature; the high 

 degree of specialization of the fourth pair of endognathites, 

 shown by the great length of the joints and the number and 

 Urge size of the* spines; the narrowness and proportionately 

 great length of the compound sternite; and the probability 

 of there being several compound sternites. It is evident that 

 the animal had a long, slender body with long, very strong 

 limbs. 



Prom a comparison of these parts with those of the various 

 genera of eurypterids, it appears that they do not agree very 

 closely with any. To show this, it is necessary only to point 

 out certain of the more evident differences. In Eurypterus 

 proper the fourth endognathite, to which I consider the longer 

 of these arms to correspond, consists of nine joints, probably 

 a greater number than is possessed by the other; besides, it 

 bears no spines except the two formed by the prolongation of 

 the eighth or penultimate joint. On the three anterior pairs 

 of endognathites the spines are more uniform in shape and 



