PHRACTOPORA. 



(Page 539.) 

 Pheactopoea ceistata, Hall. 

 Fig. 11. Zoarium, natural size. 

 Fig. 12. A portion of the surface. x6. 

 Fig. 13. Vertical section. x6. 



Upper Helderberg group. Falls of the Ohio. 



Pheactopoea lineata, Hall. 



Fig. 14. Surface x6. 



Hamilton group. York^ N'. Y. 



FAVICELLA. 



(Page 556.) 

 Favicella inclusa, Hall. 

 Fig. 15. A portion of the surface. x6. . 



Fig. 16. A still further enlargement, showing more distinctly the sur- 

 face characters. xl8. • 

 Fig. 1 7. A vertical section, showing internal structure. x6. 

 Hamilton group. York, JV. Y. 



667 



