114 
AUG. F. FOERSTE 
granulated, considering the small size of the specimen, 5 to 6 
granules occurring in a distance of 1 mm. Along the neck-ring 
and fixed cheeks the granules are less prominent, and along the 
anterior border of the cranidium they can be detected with 
difficulty. 
The third specimen belonging to the type series does not add 
to the information given by the preceding specimens. 
Cyphaspis arkansana Sp. nov. 
Plate XIV, Jigs 5 A, B, C 
Four pygidia are present in the type series, and of these the 
largest is 3.6 mm. in length, 5.6 mm. in width, and about 2 mm. 
in maximum convexity anteriorly. The axial lobe originally 
was 2.5 mm. in width anteriorly; at present only the cast of the 
lower surface of the pygidium remains. Originally this axial 
lobe rose strongly above the adjacent parts of the lateral lobes; 
possibly 1 mm. The greater part of the lateral lobes curves 
strongly downward toward the lateral margins of the pygidium, 
the downward curvature beginning along a line extending from 
a point 0.8 mm. from the anterior end of the lateral margin of 
the axial lobe diagonally backward and inward, so as to con- 
tinue around the posterior margin of the axial lobe in a U-shaped 
direction. Parallel to the posterior and lateral margins of the 
pygidium, along a line passing immediately posterior to the 
axial lobe, there is a faint tendency toward an outward or con- 
cave curvature, visible only under favorable illumination. It 
may be this faint outward curvature along the margin which 
suggested the reference of these pygidia to Cyphaspis, rather 
than to Calymene. 
The axial lobe bears 2 distinct rings wuth indistinct indications 
of a third ring. Posterior to these there is room enough for 3 
additional rings, but the surface of the axial lobe here usually 
is smooth. The pleural ribs are wxakly indicated. The anterior 
pair show median grooves. The third pair is too faintly indicated 
to give evidence of grooving. Nothing can be identified dis- 
tinctly farther back. 
