Lorraine Faunas of New York and Quebec 321 
specimen the length is 14.5 mm. The length of the cephalon 
along the median line is nearly 5 mm. The length of the thorax 
is 5.5 mm. The length of the pygidium, 4 mm. The length of 
the head to a line connecting the tips of the genal spines is 7.5 mm. 
The width of the head between the tips of the genal spines 
slightly exceeds 10 mm. The width of the anterior part of the 
thorax is about 9 mm. For about 6 segments, the width of the 
thorax remains about the same, but it becomes narrower pos- 
teriorly. The width of the pygidium is about 6 mm. 
The width of the posterior part of the glabella is about 3.5 mm. 
The length of the glabella, as far as the nuchal groove, is 3 mm. 
As in other species of Proetus, the glabella is slightly enlarged 
posteriorly, where it adjoins the concave curvature of the large 
palpebral lobes. A short, faint groove, scarcely 1 mm. in length, 
starts opposite the middle of the palpebral lobe and extends diag- 
onally backward, limiting the anterior part of the posterior pair 
of lateral lobes of the glabella. A second, fainter groove extends 
diagonally inward and moderately backward from about the 
anterior edge of the raised rim of the palpebral lobe. The distance 
from a line connecting the lateral terminations of this second pair 
of grooves as far as the anterior edge of the glabella is 1 mm. A 
third, still shorter and fainter pair of grooves is found anterior 
to the second pair and is scarcely visible. 
The facial suture starts slightly exterior to a point directly in 
front of the palpebral lobe, curves diagonally inward, apparently 
follows the outer edge of the lobe just below the visual surface, 
and posteriorly bends outward again at an angle of about 45 de- 
grees with a directly transverse line, cutting the posterior margin 
of the cephalon within 1.5 mm. of the longitudinal furrow limiting 
the axial lobe of the thorax, and an equal distance from the 
groove limiting the inner edge of the border of the cephalon at 
the genal angle. The visual surface is smooth and has a lunate 
form. 
At the genal angle, the marginal border of the free cheek has a 
width of about four-fifths of a millimeter. The length of the 
genal spine is 2.5 mm., in the case of the specimen here described, 
but in a larger specimen on the same rock fragment, it equals 
3.5 mm. 
Anteriorly, the glabella is distinctly defined, and is separated 
from the marginal border of the cephalon by a narrow space about 
