(ill) 8 Palxontolojia Sinica Ser. B. 



The pedicle valve is convex, more so in the beak region. The beak is broken but 

 a rostral cone is shown resting on the inner surface of the hinge area of the pedicle 

 valve. The cone is somewhat triangular in shape, little extended and separated 

 from the hinge line by two triangular depressions one on each side. The surface 

 is covered by about twenty-one simple, rounded and radiating j^lications with 

 the wider interspaces occupied by four or five fine longitudinal striae. Where the 

 weathering has not been complete concentric growth lines can be also seen. 



Measurements : 



Greatest width — 17 mm 



Hinge line = 17 mm 



Height = 13 mm 



Proportion of height to width * = 1.31 

 Davidson s Orthis calligramma gives the following measurements: 

 Fig. 8, PI. XXXV, Greatest width = 34 mm 



Hinge line = 29 mm 



Height = 29 mm 



Propoi'tion of height to width = 1.17 



Fig. la, PI. XXXV, Greatest width = 21 mm 



Hinge lins =18 mm 



Height =18 mm 



Proportion of height to width = 1.17 



Remarks: This species preserves the essential characters of Orthis calli- 

 gramma Dalman but differs in details as shown in the measurements given above. 

 Its form suggests Orthis caraudi but the plications of our shell are less rounded 

 and with the interspaces occupied by fine longitudinal strite. 



Horizon and Locality: Occurs with the preceding. Coll. C. C. Yii. (Ser. 

 No. X203; Cat. No. 3364). 



3. Orthis Calligramma Dalman, var. hupehensis Chang (var. nov.) 



PI. I, Figs. 3a-d and 4a-d. 



The holotype (Ser. No. X202, PI I,, Fig. 3a) is an external impression of 

 a, pedicle valve. It is transversely subcircular and wider than high. The hinge 

 line is a little shorter than the greatest width which lies about the middle part of 

 the shell. The ])edicle valve is convex, the central region, extending from the beak 



* The height is taken as i. 



