122 RESEARCH IN CHINA. 



slightly convex, rising to meet the frontal rim so as to form a rounded angle with the 

 latter; frontal rim or border narrow and nearly flat. 



The facial sutures cut through the frontal rim of the cephalon obliquely and 

 then extend almost directly backward to the anterior rim of the palpebral lobe ; curv- 

 ing around the latter, they pass obliquely outward and backward, cutting the border 

 of the cephalon a little back of the postero-lateral angle. 



Associated free cheek subtriangular in outline; the border is well defined and 

 extends to the facial suture; it is interrupted in advance of the facial suture by a 

 strong backward extending spine ; the body of the cheek rises with a gentle convexity 

 to the base of the eye-lobe. 



The associated hypostoma is subrhomboidal in outline, with the central portion 

 or body oval and convex ; the latter is crossed by a curved furrow a short distance 

 from its posterior margin ; a well-defined rim extends across the posterior margin, with 

 a furrow between it and the body; at the sides the rim incloses on each side an ear- 

 like projection which is about one-third the length of the hypostoma; the margin 

 incurves slightly back of the ear-like projection and then curves outward to join the 

 frontal margin so as to form a rather sharp, pointed angle. 



The associated thoracic segments have a strongly convex axis which is about 

 one-half the width of the pleural lobe ; the axis is marked on each side by a shallow 

 furrow near its front margin; whether there was a median spine present or not is 

 unknown ; the pleural lobes are nearly flat to the genal angle, where they curve some- 

 what gently downward ; they are marked by a broad, flat furrow that is nearly the 

 same width from the inner side next to the axis out to the genal angle ; at the genal 

 angle the furrow narrows gradually to where it disappears upon the falcate ter- 

 mination. 



Pygidium large, semicircular; axial lobe convex and tapering gradually; it is 

 divided by rather narrow furrows into five segments and a terminal portion which is 

 usually about as long as broad ; the terminal portion has two small nodes near the 

 posterior side just before the steep downward slope to the posterior border; pleural 

 lobes broad, slightly convex, and marked by a narrow anterior segment and four 

 strong segments that are separated by five broad furrows that terminate within the 

 border; the border is interrupted by a slight depression between each of the seg- 

 ments, but it is fairly well defined ; on its outer margin it carries seven rather strong 

 spines ; the first six on each side may be correlated with the ridges or segments on the 

 pleural lobes; the two posterior are opposite the small nodes on the posterior ter- 

 mination of the axis. 



The surface of the crust of the cephalon is marked by a minutely granulose sur- 

 face with a few large scattered tubercles ; a number of the larger tubercles occur along 

 the posterior rim, giving an almost dentate or spinose outline to the latter; the seg- 

 ments of the thorax appear to have been marked by a similar surface, as well as that 

 of the pygidium. 



The largest cephalon in the collection has a length of 17 mm., and the largest 

 pygidium 20 mm., exclusive of the spines on the border. 



The cephalon of this species suggests at once that of Teinistion typicalis (Wal- 

 cott) [plate 9, figs. 2, 20}. It differs in the character of the frontal limb and border of 

 the cephalon. The associated free cheek and pygidium also differ radically. From 

 Damesella blackwelderi [plate 10, figs, i, ic], the cephalon differs in the character of 

 the frontal limb and border, and the associated thoracic segment is of a different 

 type. It is distinguished by its straight furrow on the pleural lobe, while in D. 

 blacku'dderi the furrow is oblique ; the associated pygidia are essentially of the same 

 type. From all species of Dorypyge [plate 8] and Oleiioides this species differs in 



