THE EURYPTERIDA OF NEW YORK 193 
A longitudinal triangular depression at the middle of the frontal 
margin indicates sometimes, in compressed specimens, the location of the 
frontal shield of the doublure. The lateral eyes are very small, kidney- 
shaped, and prominent, with vertical, semicircular visual surface and placed 
so much within the margins that the distance between them is not greater 
than that from’ the eye to the margin of the carapace, as pointed out in 
the brief original description. They are also placed relatively far forward, 
their posterior ends lying in front of the transverse middle line of the 
carapace. The ocelli are separate, very distinct, and placed on a line 
connecting the posterior angles of the lateral eyes. The doublure of the 
carapace is narrow, widening slightly near the postlateral angles. 
No limbs are shown in our specimens. 
Only the first tergite of the dorsal side is shown in the type specimen. 
This is relatively narrow. Another example retains the ventral integu- 
ment of the abdomen. The operculum and the first sternite are deeply 
cleft, depressed and distinctly sutured along the middle line. The trans- 
verse lines are very distinct. 
The telson has not been observed. 
The carapace was smooth but on the sternites and postabdominal seg- 
ments are traces of small tubercles. Whitfield has observed ‘“ minute 
spinelike pustules or pointed granules . . . . arranged in irregular 
? 
transverse lines across the body.’’ Along the posterior margin of the 
dorsal side of the last segments appear four or five longitudinal folds, 
originally probably spine bases. 
Measurements. The carapace of the type specimen measures 15.5 
mm in length and 22 mm in width. The eyes are but 2.5 mm long. 
Wrinkles and the direction of the eyes show that it has suffered a slight 
oblique compression. The best preserved carapace is from Litchfield. It 
measures 17.5 X 27.4 mm. Its lateral eyes are 3 mm long and 6.3 mm 
apart. A carapace from Cherry Valley measures 25.3 x 35 mm. The largest 
obtained in the state is 30 mmlong and 45 mm wide. The type of the 
carapace of E. eriensis preserved in the Columbia University Museum 
