PLATE VI. 



Fig". I. Orthoceras chinense Foord. Nat. size p. 46 



la. Longitudinal section showing the septal necks, septal distances and 

 rate of tapering. 



lb. Cross section, with a central rounded siphuncle. 



Loc: — Lo-jo-ping, I-chang-hsien. W. Hupeh. (G. S. C. Cat. No. 2846) 



Fig. 2. Orthoceras chinense Foord. Nat. size p. 46 



2a. Longitudinal section, showing the rate of tapering and septal distances. 



2b. External view of same, showing the fine transverse strife. 



2c. Cross section. The small dark ring is not a siphuncle. It is formed 

 by cutting the septa just above the septal neck. 



Loc: — Tai-hung-shan, Nan-chang-hsien, N. Hupeh. (N.R.I. Cat. No. 17) 



Fig. 3. Orthoceras densum Yii. Nat. size p. 58 



3a. Longitudinal section, showing the very crowded septa at the apical 

 portion of the shell. 



3b. Cross section. 



Loc: — Chien-tze-kou, Nan-chang-hsien, N. Hupeh. (N.R.I. Cat. No. 27) 



Fig. 4. Proiocycloceras deprati Reed. Nat. size p, 62 



4a. Front view of an internal mould, showing the annulations and the rate 

 of tapering. 



4b. Lateral view of same, showing the annulations arched on the backside. 



Loc: — Near Sin-tan, Tze-kuei-hsien, W. Hupeh. (G.S.C. Cat. No. 2854) 



Fig. 5. Proiocycloceras deprati Reed. Nat. size p. 62 



External view of a portion of the mould with fine strife on the 

 annulations and the interspaces between them. 



Loc: — Near Sin-tan, Tze-kuei-hsien, W. Hupeh. (G.S.C. Cat. No. 2855) 



Fig. 6. Cycloceras sp. Nat. size p 63 



Portion of a mould, showing the oblique annulations and the longi- 

 tudinal and transverse strife near the upper end of the fragment. 



j^oc:— Tai-hung-shan, Nan-chang-hsien, N. Hupeh. (N.R.I. Cat. No. 35) 



(II) 94 



