Pteropoda P 

 Hyolithidse. 



Ortliotheca, Novak. 

 Orthotheca grabra Walcott. 

 PI. XIX., Fig. I. 



191 1. Ort/iothcc a j^iab)'a 'Wm.cott : Cambrian Faunas of China, p. 75, 

 pi. XIV., figs. 5, 5a. 



1913. 0?-f /lot/iecd ^s^labr (7 WM.coTi: : The Cambrian Faunas of China, 

 p. 97, pi. v., figs 23, 23a ; pi. VI., fig. 7. 



Slender tube elliptical in cross section, but little flattened on the dorsal 

 surface ; slightly attenuating below and almost straight, though some .speci- 

 mens show a very slight curvature. .Surface smooth. 



Dimensions : — The broadest specimen at hand measures 4 mm in length ; 

 this being fragmentar}-, it must certainly have exceeded 5 mm. when com- 

 plete. The longer diameter of the tube measures i.S mm. 



Localities : — The specimen examined is from Ta-hsi-tau, ITui-tso-hsin, 

 prov. Yun-nan ; found together with llclcioiuila 7-ugosa paiipt-ra in dark grey 

 earthy limestone. 



The original specimens of this species described by W.\lcott are from 

 the Middle Cambrian of Shan-si and Manchuria. 



Geological Age : — Cambrian, most probably Middle Cambrian. 



Gastropoda. 



Palaeoacmaeidae. 



Helcionella, Gr.^i!au and Shimkr. 

 Helcioneila rugosa (Hall) paupera Billlng;. 

 PI. XIX., Fig. 2. 



1S47. Mctoptoinal rugosa Hall: PaLneontology of New York, vol. I., 



p. 306, pi. LXXXIIL, figs. 6 a — c. 

 1872. Stcnothcca pauper J^illixcs : Canadian Naturalist, New Ser., vol. 



VI., p. 479. 



