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Figures 1-3 Annenoceras hatai, new species 86 



A polished vertical section in a lateral direction across 

 the conch exposing the structure of the siphuncle, and 

 a transverse section across the middle of the specimen 

 showing the relative size and location of the siphuncle. 

 Middle Ordovician, Ssuyen formation : Limestone near 

 Pen-hsi-hu, Liao-tung, Manchuria. 

 4,5. Armenoceras nanum (Grabau) 92 



4, A weathered natural vertical section showing parts of 

 the siphuncle. 



Middle Ordovician, Ssuyen formation: Near Niu-hsiu-tai 

 Liao-tung, Manchuria. 



5, A similar natural section. 



Middle Ordovician, Ssuyen formation : Near Pen-hsi-hu, 

 Liao-tung, Manchuria. 

 6, 7. Armenoceras liayasakai, new species 87 



6, A somewhat oblique polished section in a lateral direc- 

 tion across the conch, exposing the structure of the 

 siphuncle. 



Middle Ordovician, Ssuyen formation : Limestone near 

 Chiao-tou, Liao-tung, Manchuria. 



7, A polished vertical section in a lateral direction across 

 the conch. 



Middle Ordovician, Ssuyen formation : Limestone block, 

 Niu-hsln-tai, Manchuria. 



8. Annenoceras elongattim, new species 85 



A polished vertical section in a lateral direction across 

 the conch showing the structure of the siphuncle. 



Middle Ordovician, Ssuyen formation : Limestone near 

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



9. Armenoceras kidoi, new species 88 



Vertical dorsoventral section through the conch to show 



the structure of the siphuncle. (See also pi. 40, fig. 5.) 



Middle Ordovician, Ssuyen formation : Near Pen-hsi-hu, 



Liao-tung, Manchuria. 



101621—32 9 125 



