Plate G4, 



Figs. 1-5. I'miUn iinniiiiiihitd. iww siK^'cies (p. 4S.S|. 



1. Fragment of the unilamellar creeping zoarium. natural size. 



2. Ordinary and ovicelled zooecia, X 20, with the large umbo wi'll prcscrveil. 



3. Another zoarium, X 20. The umbo is broken and represented by :! t-ic.itrix. 



4. Another aspect of the zoarial surface, X 20. 



5. Interior of zooecia, X 20. showing the thick olocyst. 



Jliddle Jacksonian (Castle Ha.vne limestone) : Wilmington, Nortli Carolina. 

 Cat. No. 64151, TT.g.N.M, 

 Figs. G-9. I'orclhi planulata, new species (p. 4SS). 



6. The bilamellar type-specimen, natural size. 



7. Surface of the same, X 20. Only ordinary zooecia and an avicularian zooecium (in 



the npper corner) are shown. 



8. Interior of zooecia, X 20. Certain zooecia are divided into two parts. 



9. An abraded zoarial surface, X 20. The avicularium is seen buried in the tremocyst 



of one zooecium. An avicularian zooecium is present. 

 Middle Jacksonian (Castle Hayne limestone) : ^Yilmington. North Carolina. 

 Cat. No. 64152, IT.S.N.M. 

 Figs. 10-23. I'urclhi portent om, new .species (p. 4S9). 



10. Fragments of the bilamellar zoarium, natural size 



11. Aspect of the zooecial surface, X 20, when the tubnles are adjacent. 



12. Marginal zooecia, X 20, showing incomplete calcification. 



13. A frequent aspect of the species, X 20. 



14, 15. Two views of ovicelled zooecia, X 20. The frontal of the ovicell has minute pores. 



16. Ordinary zooecia, X 20, with well developed tubules. 



17. Surface, X 20, showing several calcified zooecia. 



IS. A strongly calcified surface, X 20. The intertubular spaces are coalesced. 



19. Ordinary and ovicelleil zooecia, X 20. The tubules give a bizarre aspect to the 



surface. 



20. Interior of zooecia, X 20, showing the pores of the olocyst surrounded by a white 



circle. 



21. Interior, X 20, showing the tremoiwres. 



22. Vertical section, X 20. 



23. Tangential thin section. X 100, illustrating structure of the tnbnies. 

 Middle Jaclssonian: Baldock, Barnwell County, South Carolina. 



Cat. No. 6415.3, U.S.N.M. 

 55899—20— Bull. 106 9 65 



