PLATE X. 

 STICTOPORINA. 



(Page 543.) 



StICTOPORINA CL/VYIFOBMIS, Hall. 



Fig. 1. A frond, natural size. 

 Fig. g. The same. x6. 



Hamilton group. Bellona^ JV. Y. 



RHINIDICTYA. 



Rhinidictya granulosa, Hall. 

 Fig. 3. A segment, natural size. 

 Fig. 4. The same. x6. 



Fig. 5. A still further enlargement of a portion of the surface, show- 

 ing more distinctly the cell apertures and surface orna- 

 mentation. 

 Lower Helderberg group. Catskill Creek, N. Y. 



STICTOCELLA. 



(Page 532.) 

 Stictocella interstriata. Hall. 

 Fig. 6. A frond, natural size. 



Fig. 7. A portion enlarged, showing the disposition of the cell aper- 

 ture?, the interapertural striations and the spinuliform pro- 

 jections in the cell tubes. 

 Hamilton group. Alden, JV. Y. 



STICTOPORINA. 



(Page 532.) 



STICTOPORINA SUBCARINATA, Hall. 



Fig. 8. An enlargement of a portion of a branch. x6. The natural 

 bize of the frond is illustrated in fig. 6, pi. xii. 

 Hamilton group. Beilona, N. Y. 



STICTOPORA. 



(Page 605.) 

 Sticfopora crescens. Hall. 



Fig. 9. A portion of a frond. x6. 



Fig. 10. A vertical section showing the form of the cell tubes, and 

 the intercellular vesicular tissue. x6. 

 Upper Helderberg group. Ontario. 



6:^8 



