188 RESEARCH IN CHINA. 
verging to its broadly rounded front margin; it is marked by four pairs of short 
furrows that penetrate obliquely inward and backward from the sides; the two 
posterior lobes outlined by the oblique furrows are roughly subtriangular in outline, 
the furrows penetrating over nearly one-third of the distance toward the center. 
The second pair appears to be represented by rather prominent, slightly convex 
tubercles, and extends about one-fourth the distance across the glabella. Viewed 
with a transverse light, the second pair of lobes appears to be a forward extension 
of the posterior pair of lobes, since the furrows back of them are not quite so deep 
as the more oblique furrow just inside of the inner postero-lateral margin of the 
second pair of furrows; the third pair of lobes extend obliquely inward and backward 
about one-third of the distance across the glabella; the fourth pair is outlined pos- 
teriorly by a rather deep furrow that increases in width from the outer margin 
inward for a short distance so as to form a shallow, triangular area. The anterior 
margin of the fourth pair of glabellar lobes is just back of a pit which occurs on the 
side of the glabella opposite the inner end of the palpebral ridge. On very finely 
preserved specimens a narrow, gently arched ridge appears to represent the exten- 
sion of the palpebral ridges on the fixed cheeks. There is also a transverse furrow 
just within the anterior margin of the glabella. The glabellar furrows and lobes 
described indicate that the glabella is formed by the union of five or possibly six of 
the original segments of one of the ancestral forms of this trilobite [see Walcott, 
1910@, pp. 237-238]. The occipital ring is separated from the glabella by a furrow 
that is rather broad and deep on each side, and narrow, shallow, and arching slightly 
forward across the center; occipital ring slightly convex, broad across the central 
portions, narrowing and terminating directly in the line of the posterior inter- 
marginal furrow of the fixed cheeks. Fixed cheeks about half as wide as the glabella, 
nearly flat within the palpebral lobe and ridge, and sloping gently down into the 
postero-lateral limb. ‘They are interrupted in front by the strong palpebral ridges 
which extend backward from a point opposite the anterior pair of glabellar furrows 
and merge into the arched palpebral lobes; in front of the palpebral ridge the 
cheeks descend rapidly and merge into the frontal limb; the postero-lateral limb is 
long and almost entirely made up of the rounded, narrow posterior rim, strong 
intermarginal furrow, and a narrow area between the furrow and the facial suture. 
Palpebral lobe of medium length; in a cephalon 18 mm. in length it has a length of 
4mm.; it is narrow and raised a little above the surface of the fixed cheeks. Frontal 
limb broad and strongly concave in large cephala, becoming less so in smaller; in 
front of the glabella it slopes rather rapidly downward and then upward with a 
gentle curve to the thin, rounded edge. Free cheeks gently convex but becoming 
slightly concave toward the outer margin in the larger specimens. The genal angles 
are extended into short spines. 
Thorax with eleven nearly transverse segments; axial lobe convex and a little 
more than one-half the width of the pleural lobes. It is strongly defined by a sharp 
angle where the segments pass into the pleural lobes. Each segment arches forward 
slightly at the center, also at the sides just before joining the pleural portion of the 
segment; the pleural lobe of each segment is transverse for about one-half its length, 
and then it curves gently down toward the falcate termination. The pleural 
grooves start just within the front rim of each segment next to the axial lobe, and, 
widening, continue with a nearly uniform width for about two-thirds of the distance 
outward and then narrow, disappearing some little distance within the termination 
of the segment. 
Pygidium large, moderately convex, with a narrow, strongly convex axial lobe 
and broad, slightly flattened margin; axial lobe five-sixths of the length of the 
