Eurypterus (?) (Dolichopterus?) prominens Hall
Eurypterus prominens Hall. Am. Ass'n Adv. Sci. Proc. 1884. 33: 420
Eurypterus prominens Hall & Clarke. Palaeontology of New York. 1888, 7: 157, pl. 27, fig. 3, 4
This species, the single eurypterid representative from the Clinton group, is based upon a carapace that was fully described by Hall and Clarke. These authors also point out the characters by which this species is distinctly different from any other species of Eurypterus. The most important 
Figure 38 Eurypterus? prominens Hall. Original figures. (From Hall and Clarke) of these is the anterior position of the eyes, which coupled with their submarginal position and the great length of the carapace (length to width as 27 : 30 or 9 : 10) gives the latter an aspect very like that of Dolichopterus, so that it would not be surprising if later discoveries prove this species closely allied to that genus. In Dolichopterus the specialization has gone a step farther and the carapace, which there is still well rounded at the anterior corners, has become subquadrate.
It maybe also mentioned that the youngest stage of E. remipes observed has the same long carapace and anterior eyes and that, tor this reason, E. prominens may represent a phylogenetically youthful type of Eurypterus, an inference that is supported by the geologic position of the species.
The ocelli have, as usual, followed the compound eyes and are situated well forward on a line connecting the posterior extremities of the lateral eyes. They mark the apex of the carapace. The uncompressed type specimen shows this head shield to have been relatively high, but its summit flattened and culminating in a broad ridge connecting the compound eyes.
The oblique linear depressions on the postlateral areas are rather faint and somewhat exaggerated in the drawing. Similar depressions
