DESCRIPTION OF GENERA AND SPECIES. 1of 
Also (86f), Fu-chéu series; about 1,000 feet (305 m.) above the white quartz- 
ite [see Blackwelder, 1907), p. 92, for general 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. 
Agnostus kushanensis Walcott. 
Plate 7, Figures 7, 7a—b. 
A gnostus kushanensis WaLcort, 1905, Proc. U.S. Nat. Mus., vol. xxrx, p. 22. (Described and dis- 
cussed as a new species essentially as below.) 
Cephalic shield moderately convex, a little wider than long, semicircular in 
outline, and slightly contracted at the postero-lateral angles; the narrow, rim-like, 
rounded border is broadest at the front, narrowing toward the postero-lateral angle, 
around which it curves, and extends about one-fourth the distance across the pos- 
terior margin of the cephalon; dorsal furrow well defined on the sides but rather 
faint in front of the large posterior lobe of the glabella. 
The glabella is formed of a posterior, slightly convex lobe, that is little more 
than one-fourth the width of the cephalon and less than one-half its length; it is 
marked a little in advance of its center by a small, pointed tubercle; in front of the 
posterior lobe there is a faintly outlined, conical extension of the glabella that differs 
more or less in form and strength in nearly every specimen of the cephalon; it is 
usually very obscure; lateral lobes moderately convex and uniting in front without 
interruption in the convexity of the surface. 
The thoracic segments associated with the cephalic and caudal shields have 
a convex axial lobe with narrow pleural lobes; the axial lobe is divided into a central 
portion and two lateral portions by narrow furrows, giving the effect of two large, 
oval tubercles between the dorsal furrow and the central portion of the segment; 
the short pleural lobe is marked by a very narrow pleural furrow a short distance 
back of its center. 
The caudal shield associated with the cephalic shield is slightly shorter in 
proportion to its width and less convex; it is bordered by a flat, rather broad rim, 
that is narrow at the front margin, gradually increasing to its greatest width behind, 
where its inner margin curves inward to form a blunt angle at the point opposite 
the axial lobe; the front margin is narrow and elevated in front of the lateral lobes, 
and bordered with a narrow, slightly convex, sharply defined axial segment. 
Axial lobe about one-third the entire width, moderately convex, and marked 
on its anterior third by an elongate, slightly elevated tubercle from which, on some 
specimens but not on others, two very faint grooves extend outward and then curve 
obliquely backward to the dorsal furrow, the front groove being opposite the apex 
of the tubercle; in some examples the axial lobe contracts opposite the central 
tubercle and expands at the frontal margin, where an oblique, very faintly defined 
furrow outlines a small, oval lobe; dorsal furrow narrow and sharply defined all 
about the central axis; back of the axis it unites and passes back into the furrow 
within the border; lateral lobes gently convex, usually about the width of the axial 
lobe near the central portions, narrowing posteriorly, and dying out at the short, 
shallow furrow at the posterior point of the axial lobe. 
Surface of cephalic and caudal shields and thoracic segments minutely punctate. 
This species differs from Agnostus chinensis Dames [1883, p. 27, plate 2, figs. 
18, 19], which occurs abundantly in the Ch’ang-hia formation, in having a short 
glabella and broader lateral lobes on the cephalic shield, and broader lateral lobes 
