PLATE LIX. 



PAGE 



Fig. 1. FENESTHALIA SANCTI-LUDOVIOI var. COMPACTA Ulr 605 



1. Poriferous face, x9, showing the four ranges of cells an<l the relative 



size of branches and fenestrules. 

 St. Louis group, Elizabethtown. Ky. 

 E. O. Ulrich's collection. 



Fig. 2. POLYPOBA BUBLINGTONEXSIS Ulr 587 



2. Specimen showing non-poriferous side. Natural size. 



2 a. Portion of same, x9. 



Burlington limestone, Henderson Co., 111. 

 Illinois State Museum. 



Fig. 3. POLYPOK A MAC-COT ANA Ulr 588 



3. Small specimen from Keokuk, Iowa, showing poriferous side. Natural 



size. 

 8 a. Portion of same, x9, showing the occasional tubercles. 



3 6. Another portion, x!8. 



3 c. Portion of a stronger example with stronger tubercles, x9. 

 Nauvoo, 111. 



3 d. Tangential section, x!8, shows character of cells at different depths. 



Keokuk group. 



E. 0. Ulrich's collection. 



Fig. 4. POLYPOBA SIMULATKIX Ulr 589 



4. Poriferous side of an example, natural size. It is partially covered by a 



species of Eridopora, 



4 a. Beverse side of a small fragment, natural size, showing the base of one 



of the root-like processes. 



4 6. Upper extremity of flg. 4, x9, showing the perfect appearance of the 



zooeoia apertures. 

 Keokuk group, Nauvoo" 111. 

 E. 0. Ulrich's collection. 



Fig. 5. POLYPOBA HALLIANA Prout 587 



5. Obverse face of an almost perfect frond, x9, showing the comparatively 



large granules which occupy the interspaces. 



5 a. Reverse of same, x9, showing the flattened sides of the branches and 



other features. 



5 b. Thin section, x 18, showing structure of zoarium at different levels. 

 5 c. Cortical substance as shown in thin sections, x 18. 



Keokuk group, Keokuk, Iowa. 



Illinois State Museum. 



