PLATE XVIII. 



PAGE 



Fig. 22. TAMIOSOMA GREGARIA. 61 



22 a. View of Mr. Conrad's original specimen, showing the internal 

 plates. 



22 b. End view of the same, showing the thickness of the walls and 

 the surface of the septa. 



22 c. Magnified view of a section of the walls and of the origins of the 

 transverse septa. 



22 d. Magnified view of a portion of the internal surface with the re 

 mains of septa. 



22 e. Section of the wall of RADIOLITES SQUAMOSA, to exhibit the sim 

 ilarity of the columnar structure. 



