PLATE XXIII. _ ^ 



Figs. lto8. CALLOPOKA DUMALIS, n. sp • • ^°' 



I to 4. Eepresentative fragments of the natural size. 



5. Surface of tlie slender piece X9. 



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

 7 and 8. Vertical and tangential sections "XIS. 



Upper third of the Trenton shales, St. Paul. 



Figs. 9, 10, 21 and 29. Callopoea qoodhubnsis, n. sp 28! 



9 and 10. Two fragments of the natural size. 

 21 . Axial region of a transverse section xi8. 



29. Surface of a specimen X9. 



Galena shales near Cannon Falls, Minn. 



Figs. 11, 12, 16, 17, 24-26, 30, 31. Callopora multitabulata Ulr 28C 



II and 12. Montiferous examples, the latter hut 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 xi8, of the Galena shales form. 



24. Vertical section of a specimen like fig 16, x9. 



25. Surface of the original of flg. 16, X9. 



26. Surface of a very finely preserved specimen xl8, 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, X9. The figure includes one of the clusters of large zocacia. 



31. Surface of a typical specimen X9. 



Figs. 13-15, 18-20, 22, 23, 27, 28. Callopora Ampla, n. sp 28] 



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 xi8, of another specimen from the same horizon and locality as 



the preceding. 



19. Vertical section of the same X9. 



20. The axial region of a transverse section of the same xi8. 



22 and 23 . Portion of one zocBcial tube of a vertical section and a tangential section, xi8, of 

 a specimen like figs. 13 and 28. Galena shales. Cannon Falls. 



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



28. Surface of the original of flg. 13, x9. 



Figs. 32 to 47. Dekatella pr^nuntia, n. sp. , and varieties. 



Figs. 32 to 38. Var. echinata, n. var 27 



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 xi8. 



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; xi8. Other parts of this section are precisely 

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

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

 from fig. 37. 



Figs. 39 to 42. Var. simplex, n, var 27 



39. 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 figs. 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 



An average tangential section xi8. Middle third of the Trenton shales at Minneapolis, 



Figs. 44 to 47. Var. mtjltipora, n. var 



44. A tangential section xi8, with very thin walls and small acanthopores. 



45 and 46. Another tangential section with stronger walls and large acanthopores, xi8, and 



several cells X50. 

 47. Vertical section xl8. 



Middle third of the Trenton shal.eSjMinneapolis. 



27 

 27 



