PLATE XXII. 
Figs. 1 to 12. CALLOPORA PULCHELLA, D. SP. secs eeee reer eect ence teense teense eset ereeeceens sees 
1to3. Three typical specimens of the natural-size, 
4, Surface of the original of fig. 3 *9. 
5. One of the depressed spaces of same X18. : 
6and 7. Two fragments, one unusually slender the other thicker than usual. 
8. Portion of the original of fig.7 where the walls are thinner and the mesopores larger than 
usual, X18. Other parts of its surface more as shown in fig. 5. 
9. Vertical section X18. 
10 and 11. Average tangential section 18 and small portion of same 50. 
12. Transverse section, natural size and one fifth of it X18. Note comparatively small size 
of the tubes in the axial region and wide peripheral region. 
Upper third of the Trenton shales, St. Paul. : 
Figs. 13 to 17. CALLOPORA PULCHELLA, Var. PERSIMILIS, ND. Val..... 2... e esses eee ee eee cree cece eee 
13. Two fragments showing the exceeding prominence of the monticules. 
14. Portion of the surface between the monticules <18. 
15 and 16. Vertical and tangential sections <18. 
17. A transverse section, natural size and portion of same 18. 
Upper third of the Trenton shales near Cannon Falls, 
Figs. 18 to 28. CALLOPORA CRENULATA, 1. SP... eee eee eee cece cee eee cee e eer ee nest eeeertenceetees 
18. A fragment of the zoarium of this species, natural size. 
19. Surface of same *9. 
20. Average tangential section x18. Another, representing a more matured condition, 
rather closely resembles fig. 10. 
21. Vertical section x18. 
22. Several tubes from the axial region of same X18, showing the wavy character of the walls. 
Portion of one of the macule and adjacent parts of a specimen that preserves the cen- 
trally perforated zocecial closures, 18. 
Upper third of the Trenton shales, St. Paul. 
Figs. 24 to 31. CALLOPORA UNDULATA UlIP....... 2... cee eee cece cee e eee tee e teen cece ceee dobpns doot 
24 and 25. Typical specimens of the natural size. 
26. A fragment with rounded monticules. These are too prominent in the figure. 
27. Nearly smooth fragment, in this respect approaching C. incontroversa. 
28. Surface of the original of fig. 25, x9. 
29. Tangential section 18. 
30. Portion of a transverse section *18. 
31. Vertical section 18. 
Middle third of the Trenton shales, St. Paul and Minneapolis. 
Figs. 33 to 836. CALLOPORA INCONTROVERSA UJY.......-..ceeese ee sees cence nec e eect ee ee cet econ ne 
33. Tangential section X18, representing part of one of the clusters of large zoccia and a 
few of those of the ordinary size. Compared with C. undulata (fig. 29) it will be noticed 
that they are of more rounded shape. 
34. The central part of a transverse section X18 
35. The axial part of a vertical section x18. At the right upper corner one of the tubes is 
drawn to its aperture. 
36. Anentire but rather short zocecial tube 18, showing the distribution of the diaphragms. 
Lower third of the trenton shales, Minneapolis. 
Figs. 37 to 41. CALLOPORA ANGULARIS, 0. SP. ... 0. ..- eee cece ee tee eee eet e eee ee eens eee se een eeees 
37. Fragment of the natural size. 
38. Vertical section X18. 
39. Tangential section showing fully matured characters, <18. 
40. Small portion of another tangential section *18 showing the slightly irregular character 
of the cells at a deeper level in the zoarium than that represented in fig. 39. 
41. (14 0n some of the plates.) Axial region of a tramsverse section 18. 
Lower third of the Trenton shales, Minneapolis. 
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