Q2 RESEARCH IN CHINA. 
Helcionella ? ? simplex (Walcott). 
Plate 5, Figure 11. 
Stenotheca simplex WaLcort, 1906, Proc. U.S. Nat. Mus., vol. xxx, p. 573. (Described and discussed 
as a new species essentially as below.) 
Shell small, depressed conical, with the apex situated about one-sixth the dis- 
tance from the front to the posterior margin, the point of the apex is broken away; 
aperture subcircular, a little broader than long. 
Surface with fine concentric strie and lines of growth and a few fine radiating 
lines. There is a trace of a shallow furrow extending from the apex toward the 
central portion of the anterior margin. 
The greatest diameter of the type and only specimen is 2 mm. 
This species differs widely from other known species from China. It may be 
compared with some varieties of the young of Helcionella rugosa, but it differs in 
the aperture being broader and in not having a rugose surface. The continuous 
concentric striz and absence of an area indicate that it is probably a gastropod, but 
its generic reference is doubtful. The flattened space or shallow median furrow 
suggests a brachiopod allied to Acrotreta, but the calcareous shell is not in accord 
with that interpretation. 
Formation and Localityx—Middle Cambrian: (C70) Oolitic limestone about 
30 feet (g m.) above the base of the Ki-chéu limestone [Willis and Blackwelder, 1907, 
p. 144 (last list of fossils)], 4 miles (6.4 km.) south-southwest of Tung-yii, Shan-si, 
China. 
Collected by Eliot Blackwelder. 
PTEROPODA. 
Genus HYOLITHES Eichwald. 
Hyolithes cybele Walcott. 
Plate 5, Figures 16, 16a—c; Plate 6, Figure 7. 
Hyolithes cybele WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxrx, p.17. (Described and discussed as 
a new species essentially as below.) 
Form an elongate, subtriangular pyramid, gradually and regularly tapering to 
an acute extremity. The apical angle of the dorsal side is about 15°. Transverse 
section rounded subtriangular; the ventral angle is rounded and the lateral angles 
are slightly rounded off. Dorsal face moderately convex and curving very slightly 
from the apex to the anterior spatulate portion. Ventral face strongly and regu- 
larly convex transversely. Aperture oblique, the margin extending on the dorsal 
side; the peristome on the ventral side is slightly curved forward. 
Surface marked by concentric, transverse, more or less obscure lines and striz 
of growth; the cast of the interior shows on the ventral face three or four obscure 
longitudinal lines, the central one of which is the strongest. 
The largest specimen in the collection has a length of 24 mm., with a width of 
7 mm. at the aperture. 
The body of the associated operculum is semicircular, moderately convex on 
the outer side externally, and concave within. The ventral wing as seen on the 
outside is semicircular-convex, rising toward a point at the center of the transverse 
side. The dorsal limb is nearly flat, rising, as far as can be determined from a broken 
specimen, at an angle of about 100° from the plane of the body of the operculum. 
