Plate 104. 



Figs. 1-4. DUiiierocchi vininns T'lricb, l!"il ( li. 741). 



1. A (liscxiidal zoiirium, X 12, witli well aeveloped zone of growth. 



2. A largei- zoariiim, X 12. 



3. A tubular zoarium, X 6, preserviiii; two ovicells. 



4. Surface, X 12, showing the ovicell. 



Lowest Eocene (Bryozoan bod at Imse of Aquia formation) : tapper Marll)oro, Mary- 

 land. 



Cat. No. l).")4.56, U.S.N.M. 

 Figs. 5, G. Pla{iiocci(i suhramosa Ulrich, 1901 (p. 700). 



5. A fragment, X 6. 



6. Surface, X 20, showing several covered apertures. 



Lowest Eocene (Hryozoan bed at 1)ase of Aquia formation) : Upper Marlboro, Jlary- 

 land. 

 Figs. 7-13. Lekijthiuiiia dichutoina Gablj and Horn, lf<62 (p. 747). 



7. Transverse section of a fragment, X 6. 



8, 9. Upper and lower fourths of the same, X 20. 



10. A reticulate zoarium, X 3, showing the folding of tlie liranches. 



11. Surface of ovicelled branch, X 12. 



12. Portion of side of a fragment, X 20. 



13. A l)roken ovicell. X 20, formed over n previous intact ovicell. 



Lowest Eocene (Bryozoan bed at liase of Aquia formation) : Upper Marlboro, Mary- 

 land. 



Cat. No. 0.54.57, U.S.N.M. 

 Figs. 14-20. Heteropora tecta Ulricli, 1001 (p. 682). 



14. Tlie small subramose zoarium, natural size. 



15. End of a l)ranch, X 6, with apertures of tubes covered l)y a pellicle. 



16. Portion of the same, X 20. 



17. 18. Surface of a branch, X 12, and a portion, X 2o. The mesopores and zooecia are 

 equally large. 



19. Tangential thin section, X 25. 



20. Portion of a transverse thin section, X 25. 



Lowest Eocene (Bryozoan bed at base of Aquia formation) : Upper Marlboro, Mary- 

 land. 



Cat. No. 654.58, U.S.N.M. 

 55899— 20— Bull. 106, Vol. 2 14 105 



