(xi) ,f^ P al'xontologia Sinica Ser. B. 



Vaginoceras multiplectoseptatum Yii (sp. nov.) 

 Plate v., Figs. 5 and 6. 



This species is represented by many specimens of the internal molds, which are 

 badly preserved. Some of them reveal nothing in the longitudinal sections, but others 

 show important internal structures. Shell subcylindrical, straight, elHptical in trans- 

 verse section, having two diameters at the ratio of nearly 7:6. Larger extremity not 

 observed. The expansion of the ectoconch is very slow, being i in 15 mm. 



The ectosepta are very crowded, and nearly equally separated from one another, 

 attaining a distance of 1)9 the major diameter of the ectoconch at the lower preserved 

 end and i/io at the upper. They are provided with tubi which continue beyond the 

 preceding septum. Concavity of ectosepta not more than the depth of two camene. 



The endoconch is subelliptical in section, lying at the extremity of the longer 

 diameter and close to the outer conch. It measures 14 mm. in the major diameter and 

 II mm. in the minor, where the corresponding measurements of the diameters of the 

 ectoconch are ^^ mm. and 27 mm. respectively. In general the inner shell is about 2/5 

 as large as the outer one. 



Both endoconch and the camerns are absolutely free from the organic or even the 

 inorganic deposit. The ectosepta are well preserved in some specimens, but partly 

 crushed in others. The ectotheca has not been preserved. 



Comparison: Our species bears much resemblance to Vaginoceras niiifonne, but the 

 latter has not the following characters which are characteristic of the former: i, ecto- 

 septa being more closely set, at a very short distance in their separation; 2, phragmacone 

 enlarging much more slowly; 3, concavity of ectosepta being much deeper; 4, endoconch 

 lying at the end of the major diameter instead of the minor; 5, organic deposit absolutely 

 absent. It may be also distinguished from Vaginoceras reedi by the subeUiptical, 

 marginal and smaller endoconch. Even though the numerous ectosepta and some other 

 aspects of this species are quite like those of Vaginoceras vaginatum Schlotheim*. our 

 shell has the smaller and subelliptical endoconch as well as the slower tapering, which 

 are readily differentiated from those of vSchlotheim's form. 



Horizon and Looamty: From the upper Neichiashan formation near Sintan. 

 western Hupeh. The specimens were collected b}^ J.L. Smith and C.Y. Hsieh respectively- 



I. Foord: Catalogue of Fossil Cephalpoda, Part I, p. 140. 



