(ii) £6 Palasontologia Sinica Ser. B. 



Comparison: This species agrees in some repeats with Cameroceras brainerdi 

 Whitfield' from the Fort Cassin beds along the shore of Lake Champlain, but our shell 

 has an endoconch of circular section and the rate of tapering is much more rapid. 

 Another one nearer to this is Cameroceras tenuiseptum HalP, but the present form 

 differs from it in having an elliptical shell section, a smaller endoconch and the relative- 

 ly more separated ectoseptal distances. From the preceding variety of that species the 

 present shell differs in having the circular and smaller endoconch. 



HoRTzoN AND Locat.ity: Only one specimen was obtained from the upper Neichia- 

 shan formation near Sin-tan by Mr. Hsieh, in whose honour the specific name is given. 



Cameroceras subtile Yii (sp. nov.) 

 Plate I., Figs. 5 a-b. 



This species is known only from a fragmentary phragmacone, which is straight 

 and cyhndrical in external form. Both the cross sections of the ectoconch and the 

 endoconch are elliptical. The two diameters of the ectoconch have the proportion of 

 3:2. This fragment reaches a length of a little less than 60 mm. The rate of growth 

 may be computed as 1:10 approximately. 



The ectosepta are distant almost uniformly, being about 5 mm., while the 

 ectoconch measures 28 mm. in longer diameter at the lower preserved end and 31 mm. at 

 the upper. The ectoseptal sutures are flexuous with a strong concavity exceeding the 

 depth of one camera. The latter are filled with yellowish red matrix. The ectosepta are 

 lined by a thin layer of the organic stereoplasm about one half millimeter in thickness. 

 The tubi are visible, extending a short distance beyond the preceding septum. 



The endoconch is provided with an endotheca, which is clearly shown even to the 

 naked eye. It attains a maximum width of about 1/3 that of the outer shell. It is 

 subcentral in position but does not contain the endosepta in this fragment. The 

 ectotheca has been completely weathered away and the surface of the internal mold only 

 shows the undulating ectoseptal edges. 



1. Ruedemann: Cephalopoda of ithe Beekmantown and Chazy formation of the Champlain 

 Basin, p. 405, pi. i, figs. 5, 6, pi. II, fig. i. 



2. loc. cit. 



