PLATE XXXII. 
Fig. 1. 
Fig. 2. 
Fig. 3. 
Fig. 4. 
Fig. 5. 
Fig. 6. 
Fig. 7. 
Fig. 8. 
Fig. 9. 
Fig. 10. 
Fig. 11. 
Fig. 12. 
Fig. 13. 
Fig. 14. 
Fig. 15. 
Fig. 16. 
Fig. 17. 
Fig. 18. 
Fig. 19. 
Fig. 20. 
Lichenalia OVATA. 
Page 80. 
A fragment of a frond, natural size. 
An enlargement of a portion of the surface, to show the form and arrangement of the cell 
apertures. (X 6.) 
A portion of the surface still further enlarged, showing broadly ovate cell apertures with the 
denticulations more or less distinct. (X IS.) 
An enlargement, showing the apertures more nearly circular and usually destitute of denticu¬ 
lations. (X 18.) 
A section, showing the vertical non-septate cells with the intercellular space regularly sep¬ 
tate. (X 6.) 
Upper Helderberg group. Falls of the Ohio river. .■> 
Lichenalia bistriata. 
Page 79. 
A fragment of a frond, natural size. 
A portion of a surface of fig. 6 enlarged, showing one of the maculae and adjacent cells. (X 6.) 
An enlargement from a surface which has been weathered, partially obliterating the peris¬ 
tomes. (X 18.) 
An enlargement, showing the character of the cell apertures when well-preserved. (X 18.) 
A vertical section, showing the cells without septa, the intermediate space being vesiculose or 
regularly septate. (X 6.) 
A fragment of another specimen, natural size. 
An enlargement of the surface which has been somewhat weathered, showing the lunate form of 
the apertures. (X 6.) 
A portion of the surface enlarged, showing the character of the cell apertures when in a perfect 
condition. (X 18.) 
A vertical section, showing the cells without septa, with the intermediate space regularly 
septate. (X 6.) 
Upper Helderberg group. Falls of the Ohio river. 
80h> (anil ii.ic . . n't'' • ...i . || •• i'r •. ... hi. -.it t . ,. | / 
Fistulipora intercellata. 
Page 87. 
A fragment of a specimen, natural size, incrusting a Fenestella. 
A portion of the same enlarged, showing the form and arrangement of the cell apertures and 
intermediate pits or mesopores. The surface is partially covered by other organisms. (X 6.) 
A fragment of another specimen, natural size. 
An enlargement of the preceding, showing the cell apertures larger and more closely arranged 
than in fig. 16. (X 6.) 
A portion of the specimen fig. 17, still further enlarged, showing the character of the cell aper¬ 
tures and the mesopores. (X 18.) 
A vertical section, showing the non-septate cells and the septate interspaces. 
Upper Helderberg group. Falls of the Ohio river. 
