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, 1907a, 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 C54, Upper Cambrian, lower part of 
Ch’au-mi-tién limestone [Blackwelder, 19074, p. 42 (part of last list of fossils)], near 
top of limestone knoll two-thirds of a mile (1.1 km.) west of Tsi-nan, Shan-tung, 
China. 
Pterocephalus ? liches Walcott. 
Plate 14, Figure 8. 
Pterocephalus ? liches WaL.cottT, 1911, 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. busiris [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: (85n) Fu-chéu series, limestones 
near the base of the series just above the white quartzite [see Blackwelder, 1907), 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. 
Shantungia WaLcott, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 87. (Genus characterized.) 
Not Shantungia 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 of Shantungia 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 spinifera Walcott. 
