PLATE XXV. 

 HERNODIA. 



(Page 596.) 

 Heenodia humipusa, Hall. 



Fig. 1. A colony incrusting Gomphoceras abruptum^ natural size. 

 Fig. 2. An enlargement from the preceding, showing more distinctly 

 the form of the cells and their mode of growth. x6. 

 Hamilton group. Cazenovia, N'. Y. 



CYSTOPORA. 



;(Page 598.) 



CtSTOPORA GENICULATA, Hall. 



Fig. 3. A fragment, natural size. 



Fig. 4. An enlargement, showing the ampulliform cell tubes and the 



constricted apertures. x6. 

 Fig. 5. A still further enlargement, showing more distinctly the 

 features illustrated in fig. 4. xl8. 

 Upper Helderberg group. Maiilius, N'. Y, 



CLONOPORA. 



(Page 598.) 

 Clonopoba incueva, Hall. 



Fig. 6. An enlargement, showing the form and arrangement of the 

 cell tubes. x6. 

 Upper Helderberg group. Manlius, iV^ Y. 



C1.ONOPOEA SEMIEEDUCTUS, Hall. 



Fig. 7. An enlargement, showing the form of the cell tubes and their 

 mode of growth. x6. 

 Upper Helderberg group. . Jfalls of the Ohio. 



REPTARIA. 



(Page 599.) 

 Reptaria stolonifera, Rolle. 



Fig. 8. Colonies incrusting Orthoceras constrictum, natural size. 

 Fig. 9. An enlargement, showing more distinctly the form of the 

 cells and their mode of growth. x6. 

 Hamilton group. Cazenovia, JV. Y. 



668 



