DESCRIPTION OF GENERA AND SPECIES. 133 
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. 
Ptychoparia ligea Walcott. 
Plate 12, Figure 11. 
Ptychoparia ligea WALcorT?, 1905, Proc. U.S. Nat. Mus., vol. xx1x, p. 79. (Described as a new species 
as below.) 
Cephalon, exclusive of free cheeks, subquadrilateral in outline, moderately con- 
vex. Glabella almost of the same width from the posterior margin to the rounded 
front; three pairs of furrows are faintly but clearly indicated; occipital ring strong; 
occipital furrow shallow but extended out on the lateral limbs as a strong furrow. 
Fixed cheeks nearly as wide as the glabella; palpebral lobes short and small; 
palpebral ridges narrow and strongly defined; frontal limb slightly convex to where 
it merges into the broad, shallow furrow that extends nearly out to the front margin; 
postero-lateral limbs rather long. 
Surface slightly roughened by minute, irregular, raised lines than can only be 
seen with a strong lens. 
Formation and Locality —Lower Cambrian: (C31) Gray crystalline limestone 
in the central portion of the Man-t’o shales [Blackwelder, 19074, p. 26 (first list of 
fossils), and fig. 6 (bed 12), p. 25], at Ch’ang-hia, Shan-tung, China. 
Collected by Eliot Blackwelder. 
Ptychoparia lilia Walcott. 
Plate 12, Figures 12, 12a. 
Ptychoparia lilia Wat.cort, 1906, Proc. U. S. Nat. Mus., vol. xxx, p. 588. (Characterized as a new 
species as below.) 
This species is represented by a single fragment of a cephalon, preserving the 
glabella, the left fixed cheek,.and the frontal limb and rim. It is characterized 
by the convex glabella, marked by three short, very slightly indicated pairs of 
glabellar furrows, and the strong, rounded frontal rim separated from the glabella 
by a very short frontal limb. 
The fixed cheeks are moderately convex and marked by faint, obliquely trans- 
verse palpebral ridges, palpebral lobes unknown; frontal limb narrow, slightly con- 
vex; frontal rim strong, rounded thickened in front, and separated from the frontal 
limb by a shallow, narrow furrow. 
Surface formed by a network of fine, irregular, inosculating, very slightly 
elevated lines. This surface, when partly worn, has a punctate appearance owing 
to the shallow places between the lines. The type and only specimen of the 
cephalon has a length of 5 mm. 
The associated free cheeks have a strong, rather broad border that is continued 
posteriorly as a strong and rather long spine. 
Formation and Locality—Middle Cambrian: (C75) Limestone near the base 
of the Ki-chéu formation [Willis and Blackwelder, 1907, p. 143], 4.5 miles (7.2 km.) 
south of Wu-t’ai-hién, Shan-si, China. 
Collected by Eliot Blackwelder. 
