PLATE XII. 



CaLLOPORA CELLUL08A. 

 Page 21. 

 See Plates 13 and 23 a. 

 Fi^. 1. A fragment, natural size, showing modo of bifm-cation and the numerous lateral openings. 

 Lower Helderb«rg group. ClarksvUle, N. Y. 



Fig. 2. A simple stipe having the openings more regularly arranged. 



Lower Helderberg group. Near Catskill, N. Y. 

 Fig. 3. An enlargement of a portion of the preceding. 



Fig. 4. A piece of liraeatoue with a fragment of this species ami portions of several other fonus. 

 Fig. 5. An enlargement of a portion of a branch, showing oa^ of the fistulous openings from which radia- 

 ting stria; extend. 

 Fig. 6. A fragment, natural size, showing numerous irregulai-ly arranged openings. 

 Figs. 1-6 were originally described as CaWipora fistiitusa. Haul. (Thirty-second Rept. N. Y. State Mus. 

 Nat. Hist., p. 154. 1879.) Subsequent observation.s have shown that these specimens ai-e 

 merely forms of g7"0wth of the present species. 



Lower Helderberg group. Vlarksiille, N. Y. 

 Fig. 7. Two fragments of branching fonns, showing mode of growth, cell apertures, etc. 

 Fig. 8. A small branch. 



Lower Helderberg gi-oup. Clarhmiille, N. Y. 

 Fig. 9. An enlargement from the preceding, showing the .surface characters of the species. 



Callopora pereleoans. 



.WiiW Page 2^. 



See Plate ii a. 



Fig. 10. An iri-egrularly branching specimen, natural size. »nrd!>ii«-t' 



Lower Helderberg group. ClarksvUle, N. T. 

 Fig. 11. A more slender form with numerous branchlets. , „_ ... 



Lower Helderberg group. ClarksvUle, i\r. Y. " '' ' '^' 



Fig. 12. A small specimen with branches diverging in several directions, some of which are thickened at 



their exti-emities. 

 Fig. 13. A branching form, similar to, but raoi-e slender than the one I'epi-esented in fig. 1 1 . 



Lower Helderberg group. Clarkstnlle, N. Y. 



Fig. 14. A branch, moi-e slender in the central portion, and thickened above from the incipient branching. 



Fig. 15. An enlargement of fig. 10 showing surface characters. 



Fig. 16. A longitudinal section showing cell tubes, tlieir mode of growth and divergence from the axis. 



Lower Helderberg group. ClarksvUle, N. Y. 

 Fig. 17. The cell tubes and intermediate cellular interspaces, as seen in a longitudinal translucent section. 



Callopora (C(elocaulis) Htale. 



I'aso IG. 

 See Plate 12. 

 Fig. 18. An irregularly gi-owing branch which has been partially crushed. 

 Fig. 19. An enlargement, showing the surftice characters. 



Upper Helderberg group. Onondaga Valley, N. Y. 



Callopora (CfELOCAULis) venusta. 



I'ago 23. 



See Plate 23 a. 

 Fig. 20. A slender branch, natural size. 



Lower Helderberg group. ClarksvUle, N. Y. 



Vig. 21. A larger bifurcating branch. 



Lower Helderberg group. ClarksvUle, N. Y. 



Fig. 22. An enlargement of the preceding, showing the surface characters. 



Fig. 28. An enlargement showing the interior of a bifuT-cating branch, and a portion of the epitheca. 



Lower Helderberg gi-oup. ClarksvUle, N. Y. 

 Tf\g. 34. A portion of a branch enlarging toward a bifurcation, showing constricted cell apertures, and also 



maculs without ceUa. 



Lower Helderberg group. ClarksvUlo, N. Y. 



