(ii) 4S Pal.rontologia Sinica Ser. B. 



Horizon and Localitiks: This species is very common in the argillaceous lime- 

 stone bed of the Neichiashan formation at Nei-chia-shan near Sin-tan of Tze-kuei-hsien 

 (J. S. Lee), Lo-jo-ping of I-chang-hsien (C. Y. Hsieh) and Tai-hung-shan of Nan-chang- 

 hsien (Coll. W. P. Shu and C. C. Yii). 



Orthoceras chinense var. kuangchiaoense Yii (var. nov.) 

 Plate VII., Figs, i a-c and 2. 



Shell straight, slender, subc5dindrical, regularly and gradually augmenting its 

 diameter toward the chamber of habitation at the rate of 1:8.5. The preserved part of 

 the living chamber measures 40 mm. long, the diameter at its base being 25 mm. 

 Owing to the fact that the larger extremity is poorly preserved, the aperture is unknown. 

 Shell section circular in outline. 



Only two complete camerte are preserved , increasing from 14 mm. in depth at the 

 lower camera to 17 mm. at the upper or last one. At this stage the shell diameter ranges 

 from 22 mm. to 24 mm. The septa are distant about 2/3 the diameter from each other. 

 Concavity of the septa about 1/2 the depth of a camera or more. 



Siphuncle central, circular in section, having a diameter of 2 mm., where the shell 

 is 21 mm. in diameter. The septal necks are prolonged apicad only about 1/3 the inter- 

 space between the septa. The camerse are lined with the stereoplasmic deposit about i 

 mm. thick and filled with yellowish crystalline calcite inside. 



The test is about one half millimeter thick. Its surface is covered b}' the broad, 

 undulating lamellose growth lines without any longitudinal stria>. By the aid of a lens 

 the transverse ridge are seen to be arranged in imbricating form, steepening at the 

 anterior side and sloping very gently in the other direction. They are distant about 

 I mm. 



Another individual (PI. VII, Fig. 2.) my probably be of the same form. It is 

 represented by a perfectly preserved internal mold. It has a remarkable length of 

 about 800 mm. with an acute apical termination. Transverse section unknown. It con- 

 tracts toward the posterior end at the rate of i in 7.5. The bod}^ chamber is of con- 

 siderable size, measuring-314 mm. in length and 93 mm. in width at its base. The depth 

 of the camerfe increases from 18 mm. at the diameter of 30 mm., to 35 mm. when the 

 diameter is 58 mm. The septa have a concavity equal to about 1/2 a camera height. 

 The siphuncle is entirely eroded away, but near the smaller end there is some indication 

 of the siphuncle showing its situation to be in the middle of the natural longitudinal 

 section. This specimen appears to be compressed to a certain extent, presenting a 



