PLATE IX. 



Ceplinhipods from the Earhj Upper Ordovician: — JIachiakov Limestone. 



Drawings by K. C. Liu ( $1]^^) 



Fig, 1. Actiiioccras nunnpanoidoj Grabau p. 84 



la. Lateral view of a characteristic specimen, shou'ing rate of tapering and distance of 



septa. Natural size, 

 lb. End view of same. The right side is slightly crushed. Natural size. Machiakou 



limestone, W^n-Nan, Mon-Yin-Hsien Shantung, V. K. Ting coll. (Cotype, G. S. 



Ch. Cat. No. 111). 



Fig. 2. Artiiujccras nanuin. Grabau p. 87 



A natural section, showing the very slight amount of stereoplasm. Natural size. 

 Machiakou limestone, Tangshan, Chihli. (Paratype, Survey Expedition coll. G. S. 

 Oh. Cat. No. 73) . 



Ftg. 3. Actinoceras Kvhrnarijinale Grabau , p. 86 



A weathered fragment showing the large submarginal siphuncle, and the septa and 

 nearly empty camera:^ A small part of the shell is preserved in the upper left hand 

 area. Natural size. Machiakou limestone, Tangshan, Chihli. (Cotype, G. S. Ch. 

 Oat. No. 56) . 



Fig. 4. Actinocerus richtJioJrni Freeh p. 75 



A natural weathered section, showing the forward deflection of tlie lateral diver- 

 ticula of the endosii)huncle. Natural size. (See text figure 19 p. 79). Machiakou 

 limestone, Lincheng, Shantung, , (F. F. Mathieu coll., G. S. Ch. Cat. No. 67). 



Fig. 5. Actiitocrras richthofeni Freeh p. 75 



Section of a part of a shell in which the filling of the camertE has been unusually 

 extensive. Natural size. Machiakou limestone, Huo-Luh-Hsien, Chihli. (G. S. 

 Ch. Cat. No. 64). 



Fig. 0. Actinoceras richthofeni Freeh p. 75 



Section showing part of endosiphuncle, and the moderate amount of filling 

 characteristic of the cameriu. Natural size. Machiakou limestone, Chihli (?). 

 (Coll, V. K. Ting, G. S. Ch. Cat. No. 52). 



Fig, 7. Aefinoirras rieJithnJini Freeh ,..p. 75 



7a. Lateral view of a characteristic internal septate mold, showing rate of lateral 



tapering and flexuous character of suture. Natural size. 

 7b, Side view of the same specimen showing the compressed form. On the -worn part 



the deep concavity of the septa is indicated. Natural size. 

 7c. View of the polished upper end of the same specimen, showing the oval form of tlie 



shell and the corresponding oval form and centran position of the siphuncle. 



Natural size. 

 7d, Median longitudinal section of the same specimen, showing the deep concavity of 



the septa, the character of the nummuli with the median endosiphuncle, and" the 



lateral diverticula opening in pores on the outer surface of the nummuli. 



Natural size. 

 7e. Surface of the opposite half of the same specimen, separated from 7d by about 1 mm. 



Machiakou limestone, W^n-Nan, Mon-Yin-Hsien Shantung. V. K. Ting coll 



(Geol. Survey Ch. Cat. No. 107). 



Fig. 8. Aetinoccras richthofeni Freeh p. 75 



End view of a fragment of an earlier part of the shell than that shown in fig. 7. 



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