NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
85 
The septulae are rarely visible in fossil forms, although the multiporous septulae 
often leave a large communication pore. 
In the study of the fossil bryozoa we have considered that the ovicell which 
leaves a trace above the mural rim is hyperstomial. When the ovicell projects much 
A. Conopeum B. Acanthodesia 
C. Adenifera 
D. Cupuladria 
E. Heliodoma 
F Otionella 
G. Trochopora 
H. Crepis 
I. Discoflustrellaria 
Fig. 24. — Genera of Meinbraniporae without ovicell. 
A. Conopeum lacroixi Busk, 1852, X 20. Claibornian, Claiborne, Alabama. 
B. Acanthodesia savartii Audouin, 1826, X 25. Recent. 
C. Adenifera inarmata Canu and Bassler. 1917, X 20. Middle Jacksonian, near Lenuds 
Ferry, South Carolina. 
D. Cupuladria canariensis Busk, 1859, X 20. Lower Miocene of Costa Rica. 
E. Heliodoma implicata Calvet, 1907. X 30. Recent. 
F. Otionella perforata Canu and Bassler, 1917. X 20. Lower Jacksonian, Jackson, Missis- 
sippi. 
G. Trochopora bouei Lea, 1833, X 20. Claibornian, Claiborne, Alabama. 
H. Crepis longipes Jullien, X 20. Recent. 
I. Discoflustrellaria doma D’Orbigny. Cretaceous (Senonian) of France. 
over the mural rim it is closed by the operculum under the opesium, but it always 
remains open when it does not project over the mural rim. 
An ovicell closed by the operculum is often immersed, making its distinction 
from the endozooecial a matter of great care. 
