v - 7. 1 



PLATE LY. 



PAGE. 



Pig. 1. PULYPOBA INOEPTA Hall? 358 



Horizontal section showing characters of zooecia at successive 



stages. x!8. 



Niagara group, Waklron, Inl. 



-.11 



Fig. 2. POLYPORA SHUMAKDI PrOUt. 586 



2. Horizontal section, cutting the zooecia transversely at a point midway 



between their apertures and the basal layer, x!8. 

 2 a. Portion of same section where the characters of the cells just beneath 



their mouths, is shown, x!8. 

 2 6, Basal layer, x!8. 



2 c. A vertical section, x!8, showing the nearly erect zooaoia. 

 2 d. Transverse section of two branches united by a dissepiment, x!8. 



Upper Helderberg group, Utica, Ind. 



Fig. 3. POLYPOBA COETICOSA? Ulr. (See also PI. LX) ..." 596 



Horizontal section, x!8, showing structure of obverse half of zoarium. 

 Chester group, Litchfleld, Ky. 



Fig. 4. POLYPOBA CESTBIENSIS Ulr. (See also PL LX) 594 



4. Horizontal section of two branches just above a bifurcation, x!8. 

 4 a. Horizontal section of a large branch, x!8. 



4 b. Another portion of the branch shown in 4 a, showing the zoarial char- 

 acters just beneath the zooecial apertures. 

 Chester group, Sloan's Valley, Ky. 



Fig. 5. FENESTRALIA SANCTI-LUDOVICI Prout. (See also PI. LIX) 604 



Horizontal section, x!8, showing median keel and two rows of cells on 



each side. 



Warsaw beds, Warsaw 111. 



Fig. 6. THAMNISCUS SEVILLENSIS Ulr. (See also PI. LXII) 610,727 



Horizontal section, x!8. 



Lower Coal Measures, Seville, 111. 



Fig. 7. LYKOPOBA QUINCUNCIALIS Hall. (See also PI. LVIII) 583 



7. Horizontal section, x!8. Shows the inferior hemiseptum very clearly. In 



most cases it divides the cell into two distinct portions. 

 7 a. Portion of a horizontal section, x!8, showing characters just beneath 



the cell apertures. 



7 &. Vertical section, x!8, showing form of zooeoia and inferior hemisepta. 

 7 c. Transverse section of two branches, x!8. 



Chester group, Sloan's Valley, Ky. 



