(ii) S4 Palfeontologia Sinica Ser. B. 



The endoconch is not very large and situated in close juxtaposition to the flat 

 ventral side of the outer shell. It is circular in cross section, its diameter being 6 mm. 

 where the diameter of the ectoconch is about 26 mm. The continuation of the tubi is 

 beyond the next preceding ectoseptum. The endosepta are confined to the apical end 

 with a very small endosiphuncle exposed in the middle part of the endoconch. The 

 endocylinder and endocone are empty, but all the cameme are completely occupied by 

 the crystalline calcite of secondary origin interspersed with some black material. 



Another piece (PI. III., Fig. 3) probably of the same species represents a fragment 

 of the posterior part. Cross section circular Ectosepta crowded. At the smaller 

 fragmentarj/ end the ectotheca and ectosepta are detached and only the endoconch pro- 

 jects out. Ectosepta moderately concave. Ectoseptal distance about 4.5 mm. at the 

 diameter of 18 mm. As the longitudinal section is normal to the dorso-ventral diameter, 

 the endoconch at first sight seems to occupy a central position in the ectoconch, but in 

 reality it is probably marginal to the outer shell. The ectoconch has a diameter of 16 

 mm. at the lower end, where the corresponding diameter of the endoconch is 4.5 mm. 

 The endoconch and endocylinder are not preserved in the upper portion of the specimen 

 because of the direction of the section. 



There is a third specimen (PI. II., Fig. 5.) which was procured from the Tafang 

 limestone at Yang-sing-hsien. The apical portion is not preserved. The ectoseptal dis- 

 tances are less than 1/3 the diameter of the outer shell. The endoconch is circular, 

 marginal and equal to 1/4 the diameter of the ectoconch. This specimen is similar 

 to the preceding ones in all respects except the rate of tapering, which appears 

 to be more rapid, measuring i in 16. The test is partly preserved. It conists of two 

 layers. The interior layer is much thinner and covered by the very fine transverse 

 strife. The outer one is quite obscure, though it is probably smooth. 



Comparison: This species is characterized by its fairly closely set ectosepta, re- 

 latively smaller endoconch and long empty endocylinder with the endosepta limited 

 to the apical portion. It agrees in some aspects with Vaginoceras wuhlenbergi Foord,' but 

 is distinguished from the latter by its smaller endoconch and more approximate ecto- 

 septal distance. From the description of Endoceras reinhardi? BolP including 

 Orthoceras commune Angelin-Lindstrom and some others, we find that the present 

 species may be compared with Boll's form, but differs in having the shorter interspaces 

 between the ectoseptaC, which are nearly half the diameter of the outer shell in Boll's 

 species. Moreover, our shell has shown the considerably long tubi indicating a 

 Vaginoceras, but those in Boll's form have not been characterized in the description. 



1. Joe. cit. 



2. Foord: Catalogue of Fossil Cephalopoda, Pt. I, p. 145. 



