PLATE VIII. 



Ptilodictya Whiteavesi, (page 44). 



Figure 1. Restored view of the specimen from wh'ch the thin sections were 



prepared. Natural size- 

 Figure la. Portion of median ridge and lateral area of fig. 1, x 9, showing 

 relative size and arrangement of apertures of the zooecia. 



Figure 16. Tangential section, x 18, showing the internal structure of a por- 

 tion similar to that represented by fig. la. 



Figure Ic. Vertical section, x 18. 

 ^u J ' > oung examples of this species. Natural size. 



FiSTULiPORA (?) LAXATA, (page 37). 



Figure 2. Transverse section, x 18. 

 Figure 2a. Vertical section, x 18. 



MoNTTcuLipoRA PARASITICA, var. PLANA, (page 29). 



Figure 3. View of the type specimen. Natural size. 



Figure 3a. Surface of the same, x 9. 



Figure 36. Tangential section of same, x 18. 



Figure 3c. Portion of figure 36, x 50, to show the peculiar structure of the walls 



in true species of Monticulipora. 

 Figure 3d. Three tubes of a vertical section, x 18, showing the wall structure 



and varying appearance of the cystiphragms. 



DiPLOTRYPA Westoni, (page 30). 



Figure 4. Side view of the type specimen. Natural size. 



Figure 4a. Tangential section, x 18, showing relative side and arrangement of 



the zooecia and mesopores, and one of the small clusters of the 



latter. 

 Figure 46. Two portions of a vertical section, x 18, that to the right showing 



the character of the tubes in one of the "immature" regions, 



and that to the left, one of the tubes followed up through the 



next region. 



