FiSTULIPORINA CONFKRTIPOEA, Hall. 



Fig. 13. An enlargement showing the circular cell apertures and 

 nodose peristomes. 

 Lower Helderberg group. Near Clarksmlley iVi Y. 



FiSTULIPORINA PONDEROSA, Hall. 



Fig. 14. An enlargement, sTiowing the circular cell apertures, the 

 mesopores and the prominent, conical, interapertural nodes. 

 . xl8. 

 Lower Helderberg group. iVear. ClarJcsville, JV. Y, 



FiSTULIPORINA SERRULATA, Hall. 



Fig. 15. An enlargement, showing the cell apertures and mesopores, 

 the serrulated peristomes and the characters of the opercula. 

 Hamilton group. West Bloomfield, N. Y. 



661 



