Plate 123. 



Figs. 1-14. Plagioecia coiweita, uew species (p. 711). 



1, 2. The unilamellar zoarium, natural size and X 3, composed of aggregated suhcolonies. 



3. A simple zoarium, X 12, with large zone of growtli. 



4. Basal lamella of the same zoarium, X 12. 



5, 6. Simple zoarium, X 12, and portion, X 25. At the center of the zone of growth a new 

 zoarium is superposed. Many tubes are closed by calcareous lamellae (septa). 



7. Zoarium, X 6, composed of many superposed suhcolonies arranged in Domoporn form 



of growth. 



8. Lower side of a zoarium, X 6, composed of two superposed subcolonies. 



9. Interior obtained by the wearing away of the basal lamella, X 12. 



10. Median section through a simple zoarium. X 2-5. 



11. Simple zoarium with two ovicells, X 12. 



12. Portion of a zoarium with an incomplete ovicell, X 25. 



13. Fragment of zoarium, X 25, showing marginal tubes in radial rows. 



14. Longitudinal section through a zoarium formed of superposed subcolonies, X 25. 

 Middle .Tacksonian (Castle Hayne lime.stone) : Wilmington, North Carolina. 

 Upper Jacksonian (Ocala limestone) : Chipola Kiver, east of Marianna, Florida. 



Cat. Nos. 65303, 65476, U.S.N.M. 

 124 



