NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
229 
This species resembles closely Rosseliana rosselii Audouin, 1826. a recent form, 
which, however, appears first in the Priabonian of Vieentin, Italy. Rosseliana 
parvipora differs, however, in its smaller micrometric measurements {Lz— 0.36 mm. 
instead of 0.44 mm.) and principally in its small transverse opesium. 
Occurrence . — Vicksburgian (“Chimney rock” of Marianna limestone): One 
mile north of Monroeville, Alabama (rare). 
Holotype. — Cat. No. 64253, U.S.N.M. 
Genus FLORIDINELLA Canu and Bassler, 1917. 
1917. Floridinella Canu and Bassler, Synopsis of American Early Tertiary Ciieilostome 
Bryozoa, Bulletin 96, United States National Museum, p. 28. 
The ovicell is endozooecial and separated from the zooecia by a fold The 
polypidian convexity is not prominent. The opesiular indentations are large and 
rounded. The opesium is constricted by two symmetrical lateral teeth at the level 
of the opercular articulation. 
Genotype. — Floridinella vicksburgica Canu and Bassler, 1917. 
This genus is a true Floridina without onychocellarium. The following species 
must be classed in this genus: 
Floridinella (M drginaria) deshay esi Hagenow, 1851. 
Floridinella (M enibranipora) formosa lieuss, 1874. 
FLORIDINELLA VICKSBURGICA Canu and Bassler, 1917. 
Plate 82, figs. 17-26. 
1917. Floridinella vicksburgica Canu and Bassler, Synopsis of American Early Tertiary 
Cheilostome Bryozoa, Bulletin United States National Museum, p. 28, pi. 3, fig. 3. 
Description . — The zoarium is unilamellar, hollow, cylindrical, and incrusts the 
stems or small roots of algae. The zooecia are elongated, distinct, separated by 
a deep furrow ; the mural rim is incomplete, rather broad, distinct from the crypto- 
cyst. The cryptocyst is shallow, smooth, or finely granular, longer than the 
opesium; the polypidian convexity is but slightly projecting; the opesiular indenta- 
tions are large, symmetrically rounded; the opesium is elongated, constricted 
superiorly by two lateral teeth placed at the level of the operculum. 
~ . [7/0=0.20 mm. r , ■ rAs=0.50mm. 
Measurements . — Opesium , • Zooecia , 
L [Z0=O.16mm. [fe= 0.30-0.40 mm. 
V aviations .— Species with tubular zoaria are quite polymorphic, for the zooecia 
are easily deformed on account of irregularities in the substratum. In the present 
species there are wide zooecia (fig. 21) and narrow zooecia (fig. 19). The opesium 
becomes very small and the opesiules become linear (fig. 22). We have observed 
some cases of total regeneration (fig. 26) and closed zooecia perforated by a slit 
or by a pore (fig. 26). 
The noncelluliferous face (figs. 23-25) always presents small hydrostatic tuber- 
osities designed to detach the zoarium from the substratum, to creep on the 
ectocyst, and to increase the volume of the zoarium. Here the zooecia are dis- 
