PLATE XLI. 
Fenestella (Polypora) adnata. 
Page 152. 
Fig. 1. A portion of the non-celluliferous face of a frond, natural size. 
Fig. 2. The celluliferous face of fig. 1. 
Fig. 3. A portion of the non-celluliferous face of a frond, having very irregular branches, with the dis¬ 
sepiments frequently wider than the branches. (X 6.) 
Fig-. 4. An enlargement from fig. 1, showing regular anastomosing branches with slender distinct carinae 
along the middle. (X 6 ) 
Fig. 5. A portion of fig. 2, showing the character of the celluliferous face of the frond, the form and 
arrangement of the cell apertures and occasionally larger cell apertures. (X 6.) 
Fig. 6. An enlargement of a portion of the non-celluliferous face of a frond, showing regular angular 
branches without carinae, while the dissepiments are often carinated (X 6.) 
Fig. 7. A lateral view of one of the branches of fig-. 1, showing the form of the dissepiments and the small 
spines on the celluliferous face. (X 6.) 
Fig. 8. A portion of a non-celluliferous face of a frond, having very regular branches and strongly 
carinated dissepiments. (X 6.) 
Fig. 10. A portion of a macerated frond, showing nearly equal, rounded branches and dissepiments, with 
circular or sub-circular fenestrules. (X 6.) 
Upper Helderberg group. Falls of the Ohio river. 
Fenestella (Polypora) cultellata. 
Page 160. 
See Plate 36. 
Fig. 9. A portion of the celluliferous face of a fx-ond, showing vei-y distinctly the form and ari-angement 
of the cell apertures and the sharp, secui-ifoi-m elevations along the middle of the bi-anch. 
(X 6.) 
Upper Helderb'erg group. Falls of the Ohio river. 
Fenestella (Polypora) celsipora, v;u\ minima. 
Page 151. 
See Plate 35. 
Fig. 11. A portion of the cellulifei-ous face of a frond, showing the cell apertures ax-i-anged in regular 
longitudinal rows, separated by nari-ow cai-inse. (X 6.) • • 
Fig. 12. The non-cellulifei-ous face of a fi-ond, showing quadrangular fenestrules wider than the branches. 
(X 6.) 
Fig. 13. A portion of the non-celluliferous face of another specimen, showing circular fenestrules which 
ai-e narrower than the branches. (X 6.) 
Upper Heldei-berg group. Falls of the Ohio river. 
Fenestella (Polypora) celsipora, vai\ minor. 
Page 151. 
Fig. 14. An enlai-gement of a portion of the non-celluliferous face of a frond, showing the compai-ative size 
and character of the branches and dissepiments. (X 6.) 
Fig. 15. A portion of the celluliferous face of a frond. (X 6.) 
Upper Helderbei-g gi-oup. Ontario, Canada. 
