Tlate 60. 



Fios l-li! SniittiiKi fiiifiiihita Reii8s, 1S05 (p. -iVA I. 



' 1-3. Three exiimples of the massive, hollow, irregularly loljeil imiKilaniellar zoana, 



natural size. 



4. Ordinary zooecia, X 20, with median and lateral avicularia, and a strongly developed 



porous pleurocvst. This is the most frequent aspect of the species. 



5. Surface of another zoariura, X 20. The areolae are more visible and the pleuroeyst 



is irregularlv developed. 



6. Zooecia, X 20, showing the pleuroeyst developed above the olocyst, and in a few 



cases detached from it. 



7. Zoarial surface, X 20, with two ovicelled zooecia. Like the zooecial frontal, the 



ovicell is covered by a porous pleurocy.=it. 

 S. More calcified zooecia, X 20, with a separating salient thread. Sever:il closed zooecia 



are present. 

 9. Transverse thin section, X 20. The thick zooecial walls are perforated by tubules. 

 10 Transverse section, X 20, show-ing thickening of walls. 



11. Vertical section, X 6. The dark lamellae are fille<:l with calcite, thu-^ forming a rigid 

 substratum. 

 12, 1.3. Strongly calcified zooecia, X 20. The outlines of the zoueeia are lost, liut the porous 

 pleurocvst is well developed. 



14. Interior of zooecia, X 20. showing the smooth olocyst perforated laterally by snjall 



pores. 



15. Basal aspect of the zooecia, X 20. 



16. Vertical thin section, X 20, illustrating the minute structure. 



Jaeksonian (Zeuglodon zone) : Cocoa post office, Choctaw County, Alabama. 

 Cat. No. 64133, TJ.S.N.M. 



61 



