N0.1415. CAMBRIAN FAUNAS OF CHINA— WALCOTT. 15 



This species differs from P/ati/ceras chronns and /'. pcujoda in the 

 form of the outer whorl, which expands more iinifoi'ml}' and has a 

 broadly ovate section; its form also distinguishes it from l\ 

 'priiiiaivunu 



Formation and locaJitij. — Upper Cambrian, upper portion of Chao 

 Mi Tien formation, in gray oolitic limestone; Chao Mi Tien, Shang- 

 tung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



PLATYCERAS PAGODA, new species. 



Shell minute, consisting of a))out two whorls, of which the inner 

 whorl is very minute and incurved so as to be seen best from the right 

 dorsal or outer side. Whorls regularly incurved, with the plane of 

 the coiling toward thi^ right dorsal side. The section of the outer 

 whorl near the aperture is elongate oval, with the left ventral side 

 somewhat flattened. The outer whorl widens i-apidly toward the 

 aperture, especially on the right ventral (inner) side, which gives the 

 outline, when looked at from the dorsal ridge, an obliipie, unsynuuet- 

 rical appearance. 



Surface mai'ked by concentric lines of growth which arch backward 

 upon the dorsum, indicating a dorsal sinuosity in the peristome. 



Greatest diameter of the shell 2.5 nun.; dorso-vcntral diameter of 

 whorl near the aperture 1.75 mm.; greatest lateral diameter not meas- 

 urable, but apparently not more than one-half the antei'o-posterior 

 diameter. 



This species difl'ers from Platycenix clurniiiN in the size of the outer 

 whorl, minute inner whorl, and the absence of longitudinal ridges, 

 features which also distinguish it from P. prihuvruiii Billings'^' and 

 allied forms. 



Formation and locality. — Upper Cambrian, lower portion of Chao 

 Mi Tien formation; Pagoda Hill, 1 mile west-southwest of Tai An Fu, 

 Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



Genus STENOTHECA Saltei 

 STENOTHECA (?) CLURIUS, new species. 



This form is represented by the interior cast of a large, slender, 

 slightly curving shell. The cast has a length of 10 nun., with a 

 diameter where it is broken off at the end of 4 by 5 mm. The largest 

 diameter at the aperture was probably about 10 mm. 



«Can. Nat. and GeoL, YI, 1871, p. 220. 



