NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
169 
was articulated. The zooecia presents proximal punctations on the gvmnocysf as 
do certain specimens of Stamenocella mecliaviculifera. The present species differs, 
however, in its cylindrical zoarium and in its opesium which is twice as small. 
Occurrence. — Lowest Eocene (Bryozoan bed at base of Aquia formation) : Up- 
per Marlboro, Maryland (very rare). 
Holotype. — Cat. No. 63777, U.S.N.M. 
STAMENOCELLA MIDWAYANICA, new species. 
Plate 4, figs. 5-9. 
Description. — The zoarium is free, claviform, articulated (?). compressed, 
bilamellar, bearing on each face one to six longitudinal rows of zooecia. The 
zooecia are much elongated, distinct, contracted at the back, separated by a groove 
of little depth; the mural rim is flat, finely striated, enlarged at the base. The 
opesium is elliptical or somewhat oval. The radicular zooecia are perforated by a 
large round pore, and occur only at the base of the branches. The avicularium 
which is placed in the middle of the gymnocyst is cylindrical and very prominent; 
its orifice is oblique and turned toward the summit of the zoarium. 
Measurements. — Opesia 
f/m=0.24-0.30 mm. 
lfo=0.10-0.12 mm. 
„ . |ls= 0.50 mm. 
Zooecia 
/,s=0.20 mm- 
Affinities. — The club-shaped fragments of this species were not necessarily 
articulated, but unquestionably the zoarium was provided with rootlets and its 
fronds in growing away from the ancestrula became broader and broader. 
This species belongs to a group frequent in the Upper Cretaceous, which Canu 
has classed in the artificial and unfortunately named division, Bhynchotella, which 
is distinguished from Stamenocella only by the absence of known ovicells. As 
the latter are very rare in our genus, and as the number of specimens is insufficient, 
it is necessary to hesitate before founding another generic type. 
Our species differs from M e mb ranip o ra ( Flustrella) echinata D’Orbigny, 1852, 1 
in its much smaller micrometric dimensions [Lz= 0.50 mm. instead of 0.80 mm.). 
The other species of the same group cited by D’Orbigny are very vigorous, robust, 
and their zoarium is at least five times larger, so comparison is not necessary. 
Occurrence. — Midwayan (Clayton limestone) : Mabelvale, near Little Rock, 
Arkansas (common) ; 1 mile west of Fort Gaines, Georgia (very rare) ; Luverne, 
Crenshaw County, Alabama (very rare). 
Cotypes. — Cat. No. 63799, U.S.N.M. 
STAMENOCELLA ANAT1NA, new species. 
Plate 30, fig. 12. 
Description. — The zoarium is free and bilamellar; it is formed of large, flat 
fronds; the two lamellae are inseparable and back to back. The zooecia are very 
large, elongated, distinct, separated by a furrow ; the mural rim is little salient, flat-, 
1 Paleontoiogie Francaise, Terrain Cretaee, Bryozoaires, vol. 5, pi. 699. fig. 11. 
