NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
109 
of the ribs presents no sign of calcification. It is probable, however, that the ecto- 
cyst is not the only external membrane and that a chitinous cryptocyst replaced the 
calcified deposit which is wanting here. The zooecia appear thus to be both poly- 
pidian and hydrostatic. 
On the inner side of the zoarium a fine white mealy powder refills the ribs, but 
this species is easily distinguished from OtioneTla tuberosa and from O. perforata 
by its gigantic vibracula and by the entire absence of the opesial collar. 
Occurrence . — Middle Jacksonian: 31 miles south of Perry, Georgia (common) ; 
Baldock, Barnwell County, South Carolina (common). 
Jacksonian (Zeuglodon zone) : South side of Suck Creek, Clarke County, 
Mississippi (rare); Sliubuta, Mississippi (rare). 
Cotypes. — Cat. No. 63876, U.S.N.M. 
Fig. 27. — Genera of Membraniporae with endozooecial ovicell. 
A. Vibracellina capillaria Canu and Bassler, 1917, X 20. Claibornian, Caldwell County, 
Texas. 
B. Eincksina megavicularia Canu and Bassler ,1917, X 20. Middle Jacksonian, Wilmington, 
North Carolina. 
C. Ogivalina eximipora Canu and Bassler, 1917, X 20. Middle Jacksonian, Rich Hill, 
Crawford County, Georgia. 
D. Membrendoecium rectum, new species, Vicksburgian, Byram, Mississippi. 
E. Setosellina roulei Calvet, 1907, X 25. Recent. 
SECTION II. MEMBRANIPORAE WITH ENDOZOOECIAL OVICELL. 
We have recognized four genera of Membranipores provided with an 
endozooecial ovicell, a structure which distinguishes them from genera of the first 
section quite as clearly as from those which have a hyperstomial ovicell. Fur- 
thermore, these four genera do not appear to belong even to the same family. 
Hinchsina according to Norman is a member of the Flustridae. 
V ibracellina may perhaps belong to the Lunulariidae. 
Ogivalina may be referred to the Onychocellidae. 
Membrendoecium may perhaps belong to the Farciminariidae. 
