lichenalia operculata. 



Fig. 7. 



Lichenalia operculata, Hall. Pal. N. Y., Vol. VI, page 205 (not figured), 



Fig. 7. An enlargement of the surface, showing the pustulif orm apertures 

 with operculse, and the intercellular surface, which is sometimes 

 strongly striated or ridged towards the cell apertures, with the 

 intermediate space showing an uneven vesiculiform surface. 



Lichenalia tessellata. 

 Figs. 8-10. 

 Lichenalia tessellata, Hall, Pal. N. Y., Vol. VI, page 207 (not figured). 

 Fig. 8. An enlargement from the surface, showing the peculiar character 



of the cell apertures and intercellular spaces. 

 Fig. 9, A transverse section of the same, showing the distinctly circulat 



form of the cell-tubes and the intercellular tissue. 

 Fig. 10. A vertical section, showing the cylindrical cell-tubes, the septate 

 intercellular space and the basal vesicular tissue. 



fistulipoea constriota. 

 Figs. 11, 12. 

 Mstulipora constricta, Hall. Pal. N. Y., Vol. VI, page 227. 

 Fig. 11. An enlargement from the surface, showing the form of the cell 

 apertures and their constriction by the crescentic .projection. 

 The intercellular space is irregularly pustulose and pitted. 

 Fig. 12. A transverse section of the same species, showing the form of cell- 

 tubes with the irregular intercellular tissue. 



