JAX 



I'l-ATE XLI— Continued. 



Fenestella (Polypora) CELSIPORA. 



Page 150. 

 See Plate 42. 

 Ky. 16. A portion of the celluliferous face of a fi-ond, showing the ("omjiai-ative size and character of the 

  ' branches and dis.sepiments, the form and an-angeinont of the cell apertui'es and the ridges 



separating tliem. (X 6.) 

 Fig. 17. An enlargement fi-om a giitia )iei-cha cast of the impression of the celluliferous face, where the 



tissue haa been i-emoved. (X 6.) 

 Fig. 18. The non-eel lulifernus face of a frond. The branch at the left is worn so that it presents a flattened 



appearance, filiform ti.«sue, and tlie other bmncthe." ai-e still more worn and the surface entirely 



removed, showing the fibrous condition of the solid portion of the branch. (X 6.) 

 Fig. 19. A portion of the celluliferous face. The brunch on the light side of the figiu-e shows the cell 



apertures in a pei-fect condition ; the i-eniaining branches have the surface macerated and tbe 



cells filled with solid matter, making them moi'e prominent. (X 6.) 

 Fig. 20. A poi-tion of the niin-oellnliferous face of a frond, showing considerable vai'ialion in the size and 



foi-m of the fenestrnles. (X t!.) 

 Fig. 21. A portion of a specimen, in which the branches are more slender than in the pi-eceding ; the 



fenestrnles ai'C quadrangular and frequently twice the width of the branches. (X 6.) 

 Fig. 22. A portion of the celluliferous face of a frond, showing the longiludinal rows of cell apertures, the 



elevation of the central row, the narrow fenestrnles and angular dissepiments. (XI).) 



, Upper Helderberg group. Ontario, Canada. 



