PLATE XXIII. 



PAGE. 

 Figs. 1 to 8. CALLOPOKA DUMALIS, n. sp 282 



I to 4. Kepresentative fragments of the natural size. 



5. Surface of the slender piece xg. 



6. Surface of another that preserves the zooecial closures, xi8. 

 7 and 8. Vertical and tangential sections xi8. 



Upper third of the Trenton shales, St. Paul. 



Figs. 9, 10, 21 and 29. CALLOPORA GOODHUENSIS, n. sp 282 



9 and 10. Two fragments of the natural size. 

 21 . Axial region of a transverse section xis. 



29. Surface of a specimen xg. 



Galena shales near Cannon Falls, Minn. 



Figs. 11, 12, 16, 17, 24-26, 30, 31. CALLOPORA MULTITABTTLATA Ulr 280 



II and 12. Montiferous examples, the latter but slightly, from the Galena shales at Cannon 



Falls. 



16. Typical specimen from the upper third of the Trenton shales at St. Paul. 



17. Tangential section xis, of the Galena shales form. 



24. Vertical section of a specimen like flg 16, xg. 



25. Surface of the original of flg. 16, xg. 



26. Surface of a very finely preserved specimen x!8, showing the ornamental zooecial 



closures. Upper third of the Trenton shales, St. Paul . 



30. Surface of a specimen like the one from which the illustrated tangential section (flg 17) 



was prepared, xg. The figure includes one of the clusters of large zorecia. 



31. Surface of a typical specimen xg. 



Figs. 13-15, 18-20, 22, 23, 27, 28. CALLOPOKA AMPLA, n. sp 281 



13. A large irregular specimen from the Galena shales at Cannon Falls. 

 14 and 15. Two typical examples from the base of the upper third of the Trenton shales 

 near Fountain, Minn. 



18. Tangential section xi 8, of another specimen from the same horizon and locality as 



the preceding. 



19. Vertical section of the same xg. 



20. The axial region of a transverse section of the same xis. 



22 and 23. Portion of one zooecial tube of a vertical section and a tangential section, xis, of 

 a specimen like flgs. 13 and 28. Galena shales, Cannon Falls. 



27. Surface of the original of flg. 14, xg. 



28. Surface of the original of flg. 13, xg. 



Figs. 32 to 47. DEKAYELLA PR^NUNTIA, n. sp. , and varieties. 



Figs. 32 to 38. Var. ECHINATA, n. var 271 



32. Typical example of this variety. 



33 and 34. A less compressed fragment of the natural size and a portion of its surface xg. 

 35 and 36. Two portions of a tangential section xis. 



37. Vertical section of the same specimen xg. 



Lower part of the upper third of the Trenton shales near Fountain, Minn. 



38. Portion of a tangential section of a specimen from the upper part of the middle third 



of the Trenton shales at Minneapolis; xis. Other parts of this section are precisely 

 as in flg. 36, but in the portion figured the mesopores are larger and more abundant 

 than usual for this variety. The vertical section of this specimen is indistinguishable 

 from flg. 37. 



Figs. 3g to 42. Var. SIMPLEX, n, var 271 



3g. Tangential section xi8, of a specimen with thick walls. 



40. Very small portion of the superficial region of a vertical section magnified 50 diameters to 



show the minute structure of the walls and the method of depositing the diaphragms. 



41 and 42. Small portions of two tangential sections X50, the first with walls as in flgs. 39 



and 40, the second with thinner walls, parts of which are marked transversely. 

 Lower third of the Trenton shales, Minneapolis. 



Fig. 43. The TYPICAL FORM of the species 270 



An average tangential section xis. Middle third of the Trenton shales at Minneapolis. 



Figs. 44 to 47. Var. MULTIPORA, n. var 272 



44. A tangential section xis, with very thin walls and small acanthopores. 



45 and 46. Another tangential section with stronger walls and large acanthopores, xis, and 



several cells X50. 

 47. Vertical section x!8. 



Middle third of the Trenton shales, Minneapolis. 



