NO. 1458. CAMBRIAN FAUNAS OF CHINA— ]YALCOTT. 573 



Genus STENOTHECA Salter. 

 STENOTHECA ?? SIMPLEX, new species. 



Shell small, depressed conical, with the apex .situated about one- 

 sixth the distance from the front to the posterior marg-in; the point of 

 the apex is broken away; aperture subcircular, and little broader than 

 long-. 



Surface concent ricall}" striated, with 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 onh' specimen is 2 mm. 



Ohservntion.s. — This species differs widely from other known species 

 from China. It may be compared with some varieties of the young 

 of StenotJteca rugosa, but it differs in the aperture being broader, and 

 not having a rugose surface. The continuous concentric strife and 

 absence of any indication of an area show that it is a gasteropod, but 

 its generic reference is doubtful. 



Formation and locality. — Middle Cambrian, lower portion of Ki-chou 

 formation, in a brown, oolitic limestone; 4 miles south-southwest of 

 Tung-3'u-chon, Shen-si, China. 



Collected b}^ Eliot Blackwelder. 



TRILOBITA. 



Genus DORYPYGE Dames. 

 DORYPYGE RICHTHOFENI LiEVIS, new variety. 



This variet}^ is characterized by a nearly smooth surface. An asso- 

 ciated pygidium and heads of D. riclitliofeni Dames" have tubercles 

 over most of the surface. 



Formation, and locality. — Middle Cambrian; -i miles east of Fang- 

 lan-chon, Shan-si; and 4 miles south-southwest of Tung-yii-chon, 

 Shen-si, China. 



Collected by Eliot Blackwelder. 



Genus BLACKWELDERIA, new genus. 

 Genotype. — Blackxoelderia sinensis Bergeron.'' 



BLACKWELDERIA CILIX Walcott. 

 Olemides f cilix Walcott, 1905, Pnx'. U. 8. Nat. Mus., XXIX, p. 27. 



This species is represented b}" numerous specimens of the central 

 portions of the head, separated free cheeks, and associated specimens 



« China, Richthofen; IV, 1883, p. 24. 



bCalymDume f sinensis Bergeron, 1899, Bull, de la Soc. Geol. de France, 3d ser., 

 XXVli, p. 500. 



