Fauna of the Morrow Group 
245 
the entire width of the border and parallel to the outer margin 
of the cephalic shield which becomes obsolete anteriorly and 
disappears near the point where the facial suture crosses the 
border; the striations of the peripheral margin are about ten 
in number with about five on either side of this depression in 
which the surface of the cephalon is smooth, the outer three 
or four completely encircling the arc of the shield while the 
others die out anteriorly at varying distances from the front of 
the glabella. The outline of the facial sutures very sinuous, 
the sutures appearing anteriorly at the margin of the shield 
at some distance from its middle and diverging slightly in a 
broad curve posteriorly until opposite the mid-length of the 
glabella, where their direction is changed and they rapidly con- 
verge, meeting the glabella just in front of the eyes and making 
a strong arch around the palpebral lobes. Glabella much wider 
toward the front than posteriorly, the fixed cheeks crescentic 
in outline and merging with the border of the cephalic shield 
in front of the glabella, the palpebral lobes small and occupying 
slightly less of the cranidium than do the fixed cheeks; the 
posterior part of the glabella subdivided into three lobes by two 
obliquely curving furrows which separate the moderately cres- 
centic lateral lobes from the middle larger one which is con- 
tinuous anteriorly with the remainder of the glabella; there 
seem to be no transverse furrows in front of the neck furrow. 
Eye large, elliptical, many-faceted, strongly oblique, and convex 
transversely as well as longitudinally, forming an obtuse angle 
with the somewhat oblique free cheek; a small rounded ridge 
passes around the outer margin of the eye. 
Thorax unknown. 
Pygidium semi-elliptical in outline, three-fourths as long as 
wide, broadly rounded posteriorly, with a broad, smooth, oblique, 
and gently concave border which narrows very slightly an- 
teriorly; the axis strongly elevated and sharply defined from 
the lateral lobes; semi-elliptical in section; the lateral lobes* 
moderately inflated, the convexity increasing regularly from the 
grooves which separate them from the axis toward the smooth 
peripheral border. Segmentation of pygidium strong, produced 
by deep, sharp grooves which completely cross the axis but die 
out on the lateral lobes at the margin of the smooth border; 
