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, kidneyshaped, 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 integument of the abdomen. The operculum and the first sternite are deeply cleft, depressed and distinctly sutured along the middle line. The transverse lines are very distinct.
The telson has not been observed.
The carapace was smooth but on the sternites and postabdominal segments 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 × 27.4 mm. Its lateral eyes are 3 mm long and 6.3 mm apart. A carapace from Cherry Valley measures 25.3 × 35 mm. The largest obtained in the state is 30 mm long and 45 mm wide. The type of the carapace of E. eriensis preserved in the Columbia University Museum
