DESCRIPTION OF GENERA AND SPECIES. 147 



ation of the distinct transverse furrows of the axis, that extend obliquely backward 

 out to the margin, as far as can be determined ; there is a slight indication of a pleural 

 groove on the outer half of the pleural lobe. The pleural lobe is separated from the 

 broad border by a slight elevation of the point of union of the border and pleural 

 lobe, the slope of the two being approximately the same from the margin to the axis; 

 a sharp ridge originates on the front side of each pleural segment a little distance out 

 from the axis, and extends out across the border to the margin, leaving a concave 

 space between the sharp ridges over the entire extent of the border; from the elon- 

 gate terminal segment of the axis a narrow, double ridge continues backward to the 

 border, which is here slightly incurved. 



Surface finely granular under a strong lens. 



This species differs from P. asiaticus [p. 146] in the form of the segments of the 

 pleural lobes and margin. 



Formation and Locality. Upper Cambrian: (C61) a dense black limestone in 

 the upper limestone member of the Kiu-lung group [Blackwelder, 19070, pp. 37 and 

 41 (third list of fossils), and fig. 10 (bed 13), p. 38], 3 miles (4.8 km.) southwest of 

 Yen-chuang, Shan-tung, China. 



Collected by Li San. 



This species is also identified from Locality C 54, Upper Cambrian, lower part of 

 Ch'au-mi-tien limestone [Blackwelder, 19070, p. 42 (part of last list of fossils)], near 

 top of limestone knoll two-thirds of a mile (i.i km.) west of Tsi-nan, Shan-tung, 

 China. 



Pterocephalus ? liches Walcott. 

 Plate 14, Figure 8. 



Pterocephalus ? liches WALCOTT, 191 1, Smithsonian Misc. Coll., vol. 57, No. 4, p. 80, plate 14, fig. 12. 

 (Described and discussed as a new species essentially as below.) 



This species is represented by four specimens of the pygidium. It is quite 

 unlike the pygidium referred to P. biisiris [plate 14, fig. 4], and with the discovery of 

 entire specimens of the dorsal shield it may be found that the generic reference is 

 incorrect. 



The pygidia average 4 mm. in length and are finely preserved in the compact 

 limestone matrix. 



Formation and Locality. Middle Cambrian: (35 n) Fu-chou series, limestones 

 near the base of the series just above the white quartzite [see Blackwelder, 19076, p. 

 92, for general section giving stratigraphic relations], collected in a 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. 



Genus SHANTUNGIA Walcott. 



Shanttingia WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 87. (Genus characterized.) 

 Not Shanlungia LORENZ, 1906. 



As there is but one species of this genus, the description of the species includes 

 all that is known of the genus and species. The genus is characterized by the large 

 palpebral lobes, nearly smooth, truncato-conical glabella, and the long, spinose 

 extension of the front, which is unlike that of Ampyx, as the latter proceeds from the 

 glabella, while the spine oiShantungia is from the frontal rim, in the same manner as 

 that of Proampyx acuminatum Angelin [(1854) 1878, p. 26, plate 18, fig. 7], but it 

 differs radically from the latter genus and species in the character of the glabella and 

 palpebral lobes. 



Genotype. Shantungia spini/era Walcott. 



