THE EURYPTERIDA OF NEW YORK 211 
possessing a similar broad carapace and preabdomen and a still shorter 
postabdomen. The slender swimming legs of ranilarva serve at 
once to distinguish it from this Buffalo species. Its nearest relative is 
obviously the E. kokomoensis of the same locality with which 
it has many characters in comnion, notably the broad plump form of the 
body, the broad doublure and the weak development of the swimming 
legs. Its principal distinguishing character from the latter is the greater 
width of the carapace, as a comparison of figure 7, plate 17, and figure 1 
on plate 25 will readily show. In E. kokomoensis the width sur- 
passes the length by one fifth and in E.ranilarva by one third. 
It is possible that these differences are only those of sex, a point that 
at present can not be determined since the opercular appendages of 
E.ranilarva are not distinctly shown. 
A younger specimen (no. 12906, University of Chicago collection) 
[pl. 18, fig. 2] is interesting in showing a relatively broader carapace and 
preabdomen, a shorter body, and more abrupt contraction to the post- 
abdomen, which is much more slender than the rest of the body. It thus 
displays distinctly immature features, corresponding well to those observed 
in other eurypterids. 
Eurypterus ? (Dolichopterus ?) stellatus nov. 
Plate 83, figures 1-4 
Description. Carapace subtrapezoidal, width (22 mm) a little less 
than twice the length (13.5 mm). Posterior margin slightly arched for- 
ward in the middle third, lateral margins curved, flatly sigmoidal, slightly 
converging forward; frontal margin not clearly seen, but apparently gently 
convex. 
The compound eye is elongate elliptical in outline, very large, one 
third of the length of the carapace (4 mm in type specimen), situated near 
the antelateral angle; the visual surface is long and curves far inward 
at both ends. The ocelli seem to be situated behind the center of the 
carapace. _ 
oA 
