Bulletin - United States National Museum - Smithsonian Institution

14 BULLETIN 96, UNITED STATES NATIONAL MUSEUM.
least two pairs of large lateral septulse to each zooecium and only one
l)air in the vibraculum.
,, .
, ^
Measurements.—Opesium , ..„
„ .
^
fAo=0.12nini.
[lo=0.10 mm,
fZ,s=0.25mm.
Zoceciumj
^^^^,20-0.27 mm.
^r•^ 1 fZ ^'=0.25 mm.
Vibraculum , _ . „
[
/y =0,10 mm.
Occurrence.—Claibornian: Claiborne, Alabama (common).
Lower Jacksonian: Jackson, Mississippi (common).
T7/pe.—Cat. No. 62571, U.S.N.M.
SECTION II. MEMBRANIPORAE WITH ENDOZO(ECIAL OVICEII.
We liaA'e 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. Furthermore, these four genera do not
appear to belong even to the same family.
Vibracellina may perhaps belong to the Lunulariidae.
Einchsina, according to Norman, is a member of the Flustridae.
Ogivalina is possibly a member of the Onychocelliclae.
Memhrendoecium may perhaps be referred to the Farciminariidae.
In the present state of bryozoology, generic grouping in distinct
families quite frequently is necessarily artificial, arbitrary, and prob-
lematic since we lack anatomical and larval data in many cases. It
is better therefore to maintain these four genera in the present place
rather than to introduce them doubtfully into the recent families
mentioned above.
VIBRACELLINA, new genus.
Endozocecial ovicell. Auriform vibracula. No cryptocyst. No
dietellae.
Genotype.— Vibracellina capillaria, new species. Claibornian.
VIBRACELLINA CAPILLARIA, new species.
Plate 1, fig. 5.
Description.—The zoarium incrusts small shells. The zocecia are
elongate, distinct, oval, with a very small gymnocyst ; the mural rim
is convex, salient, very thin, almost capillary. The opesium is oval,
entire. The vibraculum is interzocecial, unsymmetrical ; its opesium
is oblique and bounded by two lips of which the upper one is con-
vex and sinuous. The ovicell is a distal convexity.
Affinities.—At the center of the figured zoarium may be noted two
smaller zocecia almost equal; which of these is the ancestrula can
not be discerned. It is also to be noted that excepting these, the