NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
343 
Variations. — The oral sinus disappears frequently on account of the consid- 
erable thickening of the frontal (fig. 2), but it persists at the base of the peristomie 
and is always visible in the interior (fig. 8). 
Eschara incumbens Lonsdale, 1845, is merely this same species provided with 
its ovicells. They are very large; their frontal is thickened considerably on the 
parietal olocyst — a very rare phenomenon in the Cheilostomes, where the ovicell 
is almost always of the same nature as the frontal. By dissecting the ovicell the 
apertura is always visible and very constant in form and size. The oral avicularium 
is not at all constant; it disappears over entire fronds when they have the aspect 
of Esclxara texta Gabb and Horn, 1862. Another character common to the two 
species is “ The alternate elevations and depressions of the cellular surface of this 
remarkable species give it, to the naked eye, very much the appearance of a woven 
fabric,” quite visible in our figure 3, and noted in 1862 by Gabb and Horn. 
According to the tangential section (fig. 6) the tremocyst does not appear to 
repose on a calcified olocyst. 
Affinities. — This species differs from Schizopodrella linea Lonsdale, 1845, in 
its less zooecial width (fe=0.30-0.45 mm. instead of 0.45 mm.-0.65 mm.), and 
in a single avicularium placed below the apertura and not above it. 
0 ccurrence. — Lower Jacksonian (Mooclys marl) : Jackson, Mississippi, (very 
common). 
Middle Jacksonian: Wilmington, North Carolina (very common); Eutaw 
Springs, South Carolina (common, type locality) ; Baldock, Barnwell County, 
South Carolina (common) ; near Lenuds Ferry, South Carolina (common) ; 31 miles 
north of Grovania, Georgia (rare) ; 3| miles south of Perry, Georgia (common) ; 
17 miles northeast of Hawkinsville, Georgia (rare) ; one-half mile southeast of 
Georgia Kaolin Co. Mine, Twiggs County, Georgia (rare). 
Jacksonian (Zeuglodon zone) : Cocoa Post Office, Choctaw County, Alabama 
(rare). 
Plesiotypes. — Cat. No. 64051. U.S.N.M. 
Genus STEPHANOSELLA Canu and Bassler, 1917. 
1917. Stephanosella Cantt and Bassler, Synopsis of American Early Tertiary Cheilostome 
Bryozoa, Bulletin 96, United States National Museum, p. 40. 
The ovicell is hyperstomial and embedded in the distal zooecia. It opens 
above the aperture by an especial orifice. The frontal is a smooth olocyst. No 
spines. The ovicelled zooecia have a large aperture and their avicularium is frontal. 
Genotype. — Schizoporella ( Lepralia ) biaperta Michelin, 1845. 
R ange. — J ackson ian- R ecent. 
Our genus does not exactly correspond to the Schizoporella biaperta group 
of Waters, 1913. We prefer to take into consideration the nature of the frontal 
rather than the muscular attachments, which are impossible to verify on the fossils. 
If the areolae were more frequently observed in the species of this genus, it would 
be preferable to unite them with the genus Lacerna Jullien, 1888. 
Stephanosella differs from Lacerna in its oral avicularia and in the absence 
of spines. 
