1 88 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, 

 igioa, 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 

 4 mm. ; 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 



