PLATE XLVI. 
Fenestella curvijunctura. 
Page 107. 
Fig. 1. A figure, natural size, showing the mode of growth and the disposition of the branches and dis¬ 
sepiments. 
Fig. 2. An enlargement from the preceding, showing more distinctly the appearance of the branches and 
the curved dissepiments. (X 6 ) 
Fig. 3. An enlargement from the celluliferous face, showing the form and disposition of the cell aper¬ 
tures. (X 6.) 
Fig. 4. An enlargement of a lateral view of a branch, showing the oblique dissepiments, and the nodes 
on the middle of the branch. (X 6.) 
Fig-. 5. An enlargement of a transverse section of the branches. (X 6.) 
Upper Helderbei-g group. Falls of the Ohio river. 
Fenestella (Polypoka) robusta. 
Page 156. 
See Plates 34, 37, 39 and 43. 
Fig. 6. An enlargement from the non-celluliferous face, showing very slender dissepiments, and both 
angular and striated branches. (X 6.) 
Upper Helderberg group Walpole, Ontario, Canada. 
FENESTELLA | PxiLOPORINA ?] CONFERTIPORA. 
Page 10,8. 
Fig. 7. A fragment, natural size. 
Fig. 8. An enlargement from a portion of the preceding, showing the ordinary slender branches and one 
of the larger branches. (X 6.) 
Fig. 9. An enlargement from the celluliferous face, showing the circular, crowded cell apertures, and 
occasional larger apertures. (X 6.) 
Fig. 10. An enlargement of a transverse section of several branches. (X 0.) 
Fig. 11. An enlargement of a lateral view of a branch, showing the cell apertures and a section of the 
dissepiments. (X 6). See figs. 17-21. 
Upper Helderberg group. Falls of the Ohio river. 
FenE,STELLA SINGULARITAS. 
Page ill. 
Fig. 12. A fragment, natural size. 
Fig. 13. Au enlargement from the preceding, showing- more distinctly the appearance of the branches and 
dissepiments, and the conspicuous nodes below the bifurcations. (X 6.) 
Fig. 14. An enlargement from the celluliferous face, showing the obtusely angular branches, prominent 
nodes, and the disposition of the cell apertures. (X fi.) 
Fig. 15. An enlargement of a transverse section of several branches. (X fi.) 
Fig. 16. An enlargement of a lateral view of a branch, showing sections of the dissepiments, the cell 
apertures and the distant nodes on the two surfaces. (X 6.) 
Upper Helderberg group. Falls of the Ohio river. 
FENESTELLA [PTILOPORINA ?] CONFERTIPORA. 
Page 108. 
Fig. 17. A fragment, natural size. 
Fig. 18. An enlargement from the preceding, showing more distinctly the form and disposition of the 
branches and dissepiments. (X 6.) 
Fig. 19. An enlargement from the celluliferous face of a specimen more macerated than fig. 9. (X 6.) 
Fig. 20. An enlargement of a transverse section of branches. (X 6.) 
Fig 21. An enlargement of a lateral view of a branch, showing transverse sections of dissepiments, and 
the very prominent nodes upon the celluliferous face. (X 6). See figures 7-11. 
Upper Helderberg group. Falls of the Ohio river. 
