DESCRIPTION OF GENERA AND SPECIES. IO1 



Also (36 f), Fu-chou series; about 1,000 feet (305 m.) above the white quartz- 

 ite [see Blackwelder, 19076, 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, ja-b. 



Agnosias kushanensis WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, 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 denned 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 denned 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 denned 

 furrow outlines a small, oval lobe; dorsal furrow narrow and sharply denned 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 posteriori}', 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 chineiisis Dames [1883, p. 27, plate 2, figs. 

 1 8, 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 



