PLATE LXV— Contlnacd. 



Reptakia stolonifera. 



Page 274. 

 Fip. 17. Fi-agTnenta of fronds, natural size, incrusting Orthoceras eonstrictum, showing the form and mode 



of growth. 

 Fig. 18. An enlargement from fig. 17, showing more distinctly the annulated cell tubes and their mode of 



growth. (X 6.) 

 Fig. 19. Natui-al size of a somewhat broader frond than that represented in fig. 17. 

 Hamilton group. Cazemmia, N. Y. 



Hernodia humifusa. 



Page -m. 

 Fig. 20. Natural size of fi-onds incrusting Ghmphoceras abruptum, showing the form and mode of growth. 

 Fig. 21. An enlargement from the preceding, showing more distinctly the form of the cell apertures and 

 their mode of gi-owth. 



Hamilton group. Cazenovia, N. Y. 



