THE EURYPTERIDA OF NEW YORK 303 
which undoubtedly has affected the specimen, figure g. Larger collections 
may, however, bring out the fact that we have here to deal with varietal 
differences. 
Besides the carapaces and attached first tergites, fragments of other 
parts of the test of a Stylonurus occur at Otisville and their promi- 
nent rows of tubercles suggest that they belong to this species. Most 
easily recognized among these are the tergites [pl. 53, fig. 4, 5]. Besides 
the posterior row of tubercles borne on a high crest, these show a parallel 
middle row of less distinct tubercles, which also crown a narrow ridge. 
In some a row of smaller and less distinct tubercles 1s seen posteriorly of 
the other and alternating with it. Further, densely tubercled metastomas 
of the shape of that reproduced on plate 53, figure 1 occur not infrequently. 
They probably also belong to this species. Portions of legs with longitudi- 
nal rows of tubercles [fig. 7] suggesting their reference to this species, have 
also been observed. . 
A single entire individual has been observed and, judging from the 
_ subrectangular outline of its carapace and the size and position of the eyes 
this probably represents S. myops [pl. 52, fig. 6]. Unfortunately its test 
is reduced to a film that retains no sculpturing and shows nothing but the 
outline. The most characteristic features of the specimen are its relatively 
compact form and the small length and great width of the abdomen and 
the long spurlike epimera of the segments, both of the preabdomen and 
postabdomen. The total length of the specimen is but 55 mm, its greatest 
width however amounts to 20 mm. 
Such spurlike epimera of equal relative size are possessed only by the 
large S. scoticus from the Old Red sandstone. Curiously enough 
that isolated and strange form is hike 5. myops in outline of cara- 
pace, the approximate position of the eyes and the sculpture of the ter- 
gites. It seems probable therefore that S. myops, when fully 
known, will prove a representative of the subgenus Tarsopterus of which 
S. scoticus is the type. 
Of the telson of the species, but a small proximal portion is preserved. 
