428 NEW YORK STATE MUSEUM 
Rooker farm, Pithole City, Venango co., Pa. The outline is quite reg- 
ularly semicircular; the posterior parts of the lateral margins slightly 
concave and the postlateral angles slightly produced but not into distinct 
mucros as in the original figure. The eyes are small (between one fourth 
and one fifth the length), the nodes prominent. They are separated by 
a distance about one half the breadth of the carapace. As in other speci- 
mens from sandy beds, the glabellalike ridge of the middle of the carapace 
is well preserved between the eyes and bears a distinct circular ocellar 
mound just back of the lateral eyes. This species is probably closely 
allied to Es. mansfield, 
HUGHMILLERIA: VENTRAL SURFACE OF THE CEPHALOTHORAX 
The chance exposure of the lower side of the cephalothorax in this 
genus has brought out a structure which none of the material before exam- 
ined has displayed and an illustration of the details of this structure is 
here given. In the anterior median posi- 
tion lies a relatively long plate resembling 
an inverted lyre, which is identical with the 
object described by Sarle and reproduced 
elsewhere by ourselves as the supposed 
““metastoma of Dolichopterus??’’ It is the 
epistoma. It is bounded by sharp sutures 
on the lateral margins and terminates with 
its bilobate portion in front of the mouth. 
On its posterior lobes are two sharply out- 
Text fig. 136. Hughmillerta pittstord: lined Circtilar scars indicating ‘either the 
ensis parle: Shows marginal plates of vente 
é oe ace, » eps ry , attac ie 
Sears of chehiceracy ais, antelateral’ shield; ms, attachment of muscles or more probably 
marginal shield; Je, impression of the lateral eye; : i r 2 
Be PERSO SEN aaa ae the bases of the chelicerae. This epistoma 
is flanked by two semielliptic plates, the antelateral shields, which in their 
turn are separated by distinct sutures from the marginal shields at the 
sides. The latter show a clavate widening at their posterior ends. The 
narrow posterior doublure, which is not connected with the marginal shield, 
completes the system of marginal plates on the ventral side of the cephalo- 
thorax which hold the appendages and membranes in place. 
