PLATE XXVIII. 



PAGE. 

 Figs. 1 and 2. SPATIOPORA LABECULOSA, n. sp 320 



1. Surface, X9, of a specimen with macula? of the usual size. Others may have smaller 



macula; and more numerous mesopores between the zooecia. 



2. Tangential section of same, x]8. 



Middle third of the Trenton shales, Minneapolis, Minn. 



Figs. 3 to 7. CERAMOPHYLLA FKONDOSA, n. gen. et sp 331 



3. Nearly complete frond of this species, nat. size. 



4. Small portion of its surface, ><9, showing in the lower left hand corner the greater part 



of one of the macula?. 



5 and 6. Small parts of two tangential sections, X18, the former illustrating the normal 

 development, the latter an old and more irregular arrangement, 'and greater width 

 of interspaces due to proximity to a macula. 



7. Half of a vertical section, xi8; the tubes are divided somewhat obliquely and therefore do 



not show the full length of the prostrate portion. 

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



Figs. 8 to 11. CERAMOPORELLA INCLUSA, n. sp 329 



8. Surface, X9, of an example having the apertures filled with the clayey matrix. 



9. Small portion of another example, xis. 



10. Larger part of the surface of the original of flg. 9, xg. 



11. Selected normally developed zooscium, X40. 



Lower and middle thirds of the Trenton shales, Minneapolis, Minn. 



Fig. 12. CERAMOPORELLA INTERPOROSA, n. sp 330 



Surface of an average specimen of this species xis. 

 Galena Shales near Cannon Falls, Minn. 



Fig. 13. CERAMOPORELLA DISTINCTA, Ulr 328 



Surface of a small specimen of this species from the lower third of the Trenton shales 

 at Minneapolis; *18. 



Fig. 14. DlAMESOPORA TRENTONENSIS, n. Sp 330 



Two specimens of the natural size and the surface of the upper xg. The form and ar- 

 rangement of the zooecia is a little irregular in this specimen. In others their shape 

 approximates flg. 11. 



Galena shales near Cannon Falls, Minn. 



Figs. 15 to 20. ANOLOTICHIA IMPOMTA Ulr 327 



15 and 16. Surface XQ and xis. 



17. From the axial region of a transverse section xis. 



18. Small portion of a tangential section xi8, of a specimen in which many of the lunaria 



have only two tubuli . 



19. Portion of a typical section xis. 



20. Vertical section XQ. 



Lower third of the Trenton shales, St. Paul and Minneapolis. 



Figs. 21 to 25. BTTHOTKYPA LAXATA Ulr 325 



21 and 22. Surface of a well preserved specimen xg and xi8. 

 23 and 24. Vertical and tangential sections xg. 

 25. Portion of the tangential section xis. 

 Trenton shales, Minneapolis and St. Paul. 



Figs. 26 to 28. CREPIPORA SUB^EQUATA, n. sp 322 



26 and 27. Tangential section xg and xis. 



28. Vertical section xg, the entire thickness of the zoarium being shown in the right half 



of the figure. 

 Upper third of the Trenton shales, St. Paul. 



Figs. 29 to 32. CREPIPOKA PERAMPLA, n. sp 323 



29 and 30. Vertical and tangential sections xg, the latter with the lunaria unusually disti net. 



31. Portion of the tangential section xis. 



32. Another tangential section xg, with the lunaria scarcely distinguishable. 

 Top of the Trenton limestone, Fillrnore county, Minn. 



