Plate 17 



rage 



Figures 1—1. Armciioccras cloiic/afum, new species 85 



1, 2, Two polished, vertical sections through the conch in a 



Uiteral direction, exposing the structure of the siphuncle. 



Middle Ordovician, Ssuyen formation : Limestone near 



Niu-hsiu-tai, Liao-tung, Manchuria. 

 3, 4, A polished vertical section and a cross section of the 

 conch in the upper part, showing location and size of 

 siphuncle. 

 Middle Ordovician, Ssuyen formation : Limestone near 

 Wu-hu-tsui, Liao-tung, Manchuria. 



5. Armoioceras coulhigi (Grabau) 83 



A polished vertical section through the conch in a lateral 



direction, showing the structure of the siphuncle. 

 Locality same as Figure 3. 



G. Arnicnoccras re.svsrrj, new species 83 



A partly polished section in a lateral direction across the 



conch, exposing the structure of the siphuncle. 

 Middle Ordovician, Ssuyen formation : Limestone near 

 Pen-hsi-hu, Manchuria. 



7. Cijcloceras ( ?) manchuriense, new species GS 



Basal segment of the specimen on Plate 13, Figure 11. 

 viewed from beneath, showing the relative size and loca- 

 tion of the siphuncle. 

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