Pigs. 
Pig. 
Fig. 
Fig. 
Pig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
PLATE XLIX. 
Fenestella permarginata. 
Page 127. 
1, 2, 3. Enlargements from the non-celluliferous face, showing the obscure characters of the branches 
and dissepiments. 
4. The celluliferous face, with the carinae removed, showing the arrangement of the cell apertures, 
f). A portion of the celluliferous face of a frond. The lower half of the figure shows the carinae 
united and with some vesiculose tissue in the lower part. 
6. An enlargement from the non-celluliferous face, showing numerous nodes ornamenting the 
branches and dissepiments. 
7. The base of a frond, natural size. 
8. A lateral view of a portion of a branch, enlarged. 
9. A transverse section, showing the form of the branches and carinae. 
10. A section similar to the preceding, in which the branches are larger and the fenestrules narrower. 
Upper Helderberg group. Falls of the Ohio river. 
Fenestella semirotunda. 
Page 125 . 
11. The base and lower portion of a frond, natural size. 
12. The celluliferous face of a fragment, natural size. 
13. A transverse section of several branches, showing the elevation and expansion of the carinae. 
14. A transverse section of branches more cylindrical than the preceding. 
15. An enlargement of the summits of the carinae from the lower portion of the frond where they are 
connected by vesiculose tissue. 
16. An enlargement from the non-celluliferous face, showing the involved and irregular branches and 
dissepiments. 
17. The non-celluliferous face of a specimen with more regular fenestrules. 
18. An enlargement similar to the preceding, but with stronger branches and dissepiments, and smaller 
fenestrules. 
19. The non-celluliferous side of a fragment, showing characters similar to fig. 16. 
20. The non-celluliferous face of a specimen preserving irregularly distributed nodes on the branches 
and dissepiments. 
21. The celluliferous face with the carinae removed, showing the cell apertures. 
22. The celluliferous face of a specimen showing the summits of the carinae and their irregular lateral 
expansions. 
Upper Helderberg group. Falls of the Ohio river. 
