63 



radial stride on the surface of the valves of Poranibonitcs iiitei-ccdcns MAKTErj.i 

 may make one hesitate to identify it with the same author's Triplcciix f>o[oi. 

 Yet these radial strite may be ascribed to the state of preservation, because 

 the shell possesses radial striae on the inner lamina; as explained above. The 

 rare cases in Avhich fine radial stria; occur, as remarked by Halt,, also may be 

 made clear by the method of speculation suggested by Reed. 



Localities: — i) Lo-ling-po near No-lu-ping, Tung-hu-hsien, I-chang-fu, 

 prov. Hupei ; 2) Kao-huang-ling, Hsing-shan-hsien, I-chang-fu, prov. Hu-pei. 



Geological Age : — Ordovician. This species ought to be regarded as an 

 indicative of the Ordovician Information in Eastern Asia. 



Plectambonites, Pander. 

 Pleetambonites cf. sericeus Sow. 



t 



IT. XXII., Figs. 6 and 7. 



1839, Leptacna scricca, Murciiison : — The Silurian System, pt. II., p. 



636. pi. 19, fig. I. 

 1839. Lcptacna scricca var. Mukciuson : — ditto, fig. 2. 

 1847. Lc fit acna scricca, Hall: — Nat. Hist. New York, Palaeontology, 



vol. I., p. no. pi. XXXI., fig. 2 ; p. 287. pi. LXXIX., fig. 3. 

 185 1. Lc/ytacna sericea, Halt. : — ditto, vol. II., p. 59. pi. XXL, fig. i. 

 1864. Lcptacna sericea, Davidson: — Monogr. Brit. Sil. Brach., p. 323. 



pi. XIVIIL, figs. 10-19. 

 1883. Lcptacna scricca, Kavsicr : — Von Richthohen's China, vol. IV., 



p. 41. pi. Ill,, fig. 8. 

 1892. Plectambonites scricca. Hall: — Nat. Hist. New York, Palaeon- 

 tology, vol. VIII., pt. I., pi. XV., fig. 26. 

 1906. Plectambonites scricca, Lorenz : — Beitr. z. Geol. u. Palaeont, v. 



Ostasien unter besoder. Beriicksicht. d. Prov. Schantung. Z. d. 



d. g. G., LVIII,, p. 96. pi. VI., figs. 9, 10. 

 1909. Plectambonites seriscns, Grabau and Shimer : — N. ^Vmerican Index 



Fossils, vol. I., p. 227, fig. 274. 



