I'l.ATii oi;. 



I'lGS. 1-5. PorcVti tlcnticulifi III, new species (p. 4S5). 



1. Two examples of the liihimellai' zonriiini. iinturnl size. 



2. Surface of zoarium, X 20, Tlie median uviciilai-inm, when well preserveil, appears 



as a clenticulated tube. 



3. Ovicelled zooecia. X 20. The small pores of the ovicell are in marked contrast to 



the very large treraopores. 



4. Interior of zooecia, X 20. 



5. Tangential thin section, X 100. The large trenioirores, the ovicell and apertura are 



shown in white, while the avicnlarium is in grey. 

 Lower .Jacksonian (Jioodys marl) : Jackson, Mississippi. 

 Cat. No. 64146, U.S.N.M. 

 Figs. 6-17. PurcUii jncksonica, new species (p. 4S6). 



6. Small fragments of the bilaniellar zoarium, natural size. 



7. Ordinary zooecia. X 20, showing the convexity of the frontal and the large mucro. 



This is the usual aspect. 



8. Zooecia along margin of a zoarium, X 20. The mucro is much elongated. 



9. Ovicelled zooecia, X 20. 



10. Zooecia, X 20. Adventitious avicularia are developed. The zooecia are not dis- 



tinctly marked. 

 Lower Jacksonian (Jloodys marl) : Jack.son, Jlississippi. 

 Cat. No. 64147, U.S.N.M. 



11. Another aspect of the species, X 20. The dimensions are smaller than usual. 



12. Portion of a zoarium, showing a frequent aspect of the species. The mucro is quite 



salient. 



13. Zooecia, X 20, with both the ovieells and avicularia broken, a frequent occurrence. 

 Middle Jacksonian (Castle Hayue limestone) : Wilmington, North Carolina. 



Cat. No. 6414S, U.S.N.M. 



14. Surface of an old zoarium. X 20, altered by calcification. 



15. View of the interior, X 20, showing the white circles surrounding the pores of the 



olocyst. The zooecia are indistinct. 

 Lower Jacksonian (Moodys marl) : Jackson, Mississippi. 

 Cat. No. 64149, U.S.N.M. 



16. A zoarium, X 20, with stuntefl, indistinct zooecia. 



17. Tangential thiu section of a zooecium, X 100. The apertura, avievilaria and tremo- 



pores are sho\^Ti. 

 Middle Jacksonian: Baldock. Barnwell County, South Carolina. 

 Cat. No. 64150, U.S.N.M. 

 64 



