PLATE XXVI. 
Trematopora (Trematella) annulata. 
Page 69. 
See Plate 25. 
Fig’. 1. Showing - the natural size and manner of growth. 
Fig. 2 The same, enlarged, showing the form and arrangement of cell apertures, and the annulated 
appearance of the branches. (XU) 
Upper Helderberg group. Falls of the Ohio river. 
Trematopora (Orthopora) RHOMBIFERA. 
Page 71. 
-- See Plates 11, 23 and 25. 
Fig. 3. A specimen, natural size, showing the manner of growth. 
Fig. 4'%ie same, enlarged, showing the form and arrangement of cell apertures, and granulose char- 
. acter of intercellular space. (X (3.) 
Upper Helderberg group. Falls of the Ohio river. 
Fig. 
Fig. 
Trematopora (Orthopora) regularis. 
Page 71. 
See Plates 11, 13, 23 and 25. 
5. A specimen, natural size, showing the manner of growth. 
6. The same, enlarged, showing the form and arrangement of the cell apertures, and the pustu- 
lose intercellular spaces. 
Upper Helderberg group. Falls of the Ohio river. 
Trematopora (Orthopora) scutulata. 
Page 70. 
Fig. 7. A specimen, natural size, showing the manner of growth. 
Fig. 8 The same, enlarged, showing the form and arrangement of cell apertures, and the spin tiles at 
the angles of the cell walls. ( X 6.) 
Upper Helderberg group. 
Fig- 
Fig. 
W- 
D1A M ESOPOR A CAM ER AT A. 
Page 72. 
9 A specimen, natural size. 
,'). The same, enlarged, showing the form and arrangement of cell apertures, and the non-eellulifer- 
ous spaces. (X 6.) 
Upper Helderberg group. Near Caledonia, N. Y. 
CaLLOPOBA (CcELOCAULTS) IRREGULARIS. 
Page 76. 
Fig. 11. Natural size of a specimen, showing the manner of growth. 
Fig. 12. An enlargement of tig. 11, showing the comparatively small cell apertures, which are distantly 
and irregularly arranged on one portion of the frond, and more closely arranged and with 
intermediate pits on the other. (X 6.) 
Fig. 13. Another specimen, natural size, larger than that of fig. II, and somewhat compressed. 
Fig. 14. An enlargement of one portion of fig. 13, showing cells somewhat more closely arranged than in 
fig. 12 ; with no intermediate pits, and with maculae destitute of cell apertures. (X 6.) 
Fig. 15. An enlargement of another portion of fig. 13, showing the cell apertures still larger, and arranged 
in quite regular arching transverse rows. The peristomes composing the rows are fre¬ 
quently in contact. (X 6.) 
Upper Helderberg group. Central New York. 
