128 RESEARCH IN CHINA. 



low bluff on the shore of Tschang-hsing-tau Island, east of Niang-niang-kung, Liau- 

 tung, Manchuria, China. 



Collected by J. P. Iddings and Li San. 



The stratigraphic range given this species is based upon the comparison of speci- 

 mens that appear to be identical. 



Damesella brevicaudata Walcott. 

 Plate 9, Figure 9. 



Damesella brevicaudata WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 39. (Described and dis- 

 cussed as a new species essentially as below.) 



This species is based upon a pygidium that is transversely semicircular in shape, 

 with a short, strong, convex axis. The axis is marked by two anterior transverse 

 furrows and a very shallow posterior furrow, that divide the axis into an anterior 

 ring, which joined the thorax, two faintly defined rings, and a rounded terminal sec- 

 tion; the axis rounds down abruptly at its broad, posterior end, passing into the mar- 

 gin. The dorsal furrow is narrow and clearly defined on each side of the axis. 



Pleural lobes flat for a very short distance, and then rounding downward to the 

 border; each lobe is marked by an anterior, deep, narrow furrow within the margin, 

 and four strong furrows terminate within the border ; they divide the lobes into four 

 elevated segments that merge into the irregular border; from the border fourteen 

 spines project ; the anterior spines appear to be the continuation of the anterior, ele- 

 vated margin of the pygidium and the first segment; the second, third, fourth, and 

 fifth spines are opposite the furrows between the segments and do not appear to be 

 the direct continuation of the segments, although a low ridge from each segment 

 crosses the margin obliquely to them ; two spines project back of the axis, and one on 

 each side opposite the dorsal furrow on the side of the axis. 



Surface marked by an irregular row of rather large tubercles on the rings of 

 the axis and anchylosed segments of the pleural lobes ; under a very strong lens the 

 surface appears to be slightly roughened or minutely punctate. 



Length of pygidium, 7 mm.; width in front of border, exclusive of spines, 16 mm.; 

 width of axis at anterior margin, 5 mm. 



The pygidium of this species is characterized by its short, wide, convex central 

 axis, relatively narrow pleural lobes, and very strong, spinose border. It differs 

 from Dorypyge richthofeni Dames [p. 108] in its short, broad axis and the character 

 of the pleural lobes and spinose border. 



Formation and Locality. Middle Cambrian: (C19) Uppermost layers of the 

 Ch'ang-hia limestone [Blackwelder, 19070, p. 33 (part of the last list of fossils)], at 

 Ch'ang-hia, Shan-tung, China. 



Collected by Li San. 



Damesella sp. undt. (c). 

 Plate 9, Figure 12. 



Only the matrix of a pygidium is known of this form. This has a strong 

 median lobe divided by four narrow transverse furrows into four segments and a 

 broad terminal section that touches the border. The axial segments continue out 

 on the pleural lobes to where they merge into the border. 



The pleural segments do not show a furrow and in this respect are similar to 

 the pleural segments of the pygidium of Damesella blackwelderi [plate 10, figs. ie-j}. 



The tuberculate surface is much like that of D. blackwelderi, and I would 

 identify the pygidium with the latter species except that it occurs several hundred 

 feet lower in the section studied by Prof. J. P. Iddings. 



