PLATE IV. 



Fig. I. Vaginoceras wahlenbergi Foord var. cylindrica Yii. Nat. size p. 32 



Longitudinal section, showing the endocyUnder, the ectosepta and the 



rate of tapering. 



Loc: — He-chiao, Chung-yang-hsien, SE. Hupeh. (N. R. L Cat. No. 5) 



Ficr. 2. Vaginoceras wahlenbergi Yooxd wds. cylindrica Y^i. Nat. size p. 32 



2a. Natural polished section, showing the rate of tapering and the depth 

 of ectosepta. 



2b. Longitudinal section with a large endocylinder. The section'does 

 not pass through the middle part of the endocylinder in the 

 upper part of the specimen. 



Loc: — Liu-chia-sze, Hsien-ning-hsien, SE. Hupeh. (N.R.L Cat. No. 6) 



Fig. 3. V aginoceras shut Yii. Nat. size p. 37 



3a. A natural polished longitudinal section, showing the very long tubi, 

 endosepta, depth of ectosepta and the rate of tapering. 



^,b. Cross section with a submarginal endoconch. 



Loc: — Wang-chia-sze, Chung-vang-hsien, SE. Hupeh. (N. R. L Cat. 



No. II) 



Fig. 4. Orthoceras chinense Foord. Nat. size p. 46 



4a. Longitudinal section, showing the tapering, the septal necks and the 

 depth of camerte. 



4b. Cross section, showing the form of shell and the size of the central, 

 circular siphuncle. 



Loc: — Near Sin-tan, Tze-kuei-hsien, W. Hupeh. (G.S.C. Cat. No, 2844) 

 Fig. 5. Orthoceras regidare Schlotheim. Nat. size p. 52 



Longitudinal section, showing the septal necks, septal distances and 

 the rate of tapering. 



Loc: — Near Sin-tan, Tze-kuei-hsien, W. Hupeh. (G.S.C. Cat. No. 2848) 



Fig. 6. Orthoceras regidare Schlotheim. Nat. size p. 5? 



6a. Longitudinal section, showing the tapering, the septa and septal necks. 



6b. Cross section, showing the form of shell and the position of siphuncle. 



Loc:— Near Sin-tan, Tze-kuei-hsien, W. Hupeh. (G.S.C. Cat. No. 2849) 



Fig. 7. Orthoceras squamutulimi Barrande. Nat. size p. 5 



J 



(II) 8( 



