Bulletin - United States National Museum - Smithsonian Institution

EARLY TEKTIARY CHEILOSTOME BRYOZOA. 47
Occurrence.—Vicksburgian ; 1 mile north of Monroeville, Alabama
(very common).
Type.—Cat. No. 62594, U.S.N.M.
SCHIZEMIELLA, new genus.
(Schizos, slit; emi, abbreviation of peristomie.)
The frontal of the ovicell is very fragile. The apertura is schizo-
porelliclan with wide rimiile. The rimiile-spiramen is inconstant.
The tubules are reimited on their commonage.
Genotype.— Schizemiella claibornica, new species. Claibornian,
SCHIZEMIELLA CLAIBORNICA, new species.
Plate 4, fig. 9.
Description.—The zoariiim is free, bilamellar with inseparable
lamellae. The zocecia are indistinct; the frontal is thickened, little
convex, formed of a tremocyst with large irregular tubules placed on
a thin olocyst with very small pores in quincunx. The apertura is
formed of an ogival anter and a concave poster with a very wide
rimule ; the peristomice is elongated, embedded, with a very wide, ir-
regular rimule-spiramen. The ovicell is hyperstomial and opens
largely into the peristomie; it is little globular, hardly salient; covered
by a smooth or perforated, very fragile wall ; the peristomice is
elliptical and transverse. The avicularium is triangular, the beak
directed above, adjacent to the peristomice which it deforms, provided
with a pivot.
T. •.•/.• \hpe^0.20 mm.
X
Measurements.—Peristomice (exterior) | , —014—0 16 mm
,. ^ . , [^.=0.12
mm.
Apertura (interior) 1^^^^^^^^^
„ .,.,.. [Ls=0.54: mm.
Zocecia (interior) , „ „„
^ ^ [?2=0.30 mm.
Variations.—In the interior the tremopores are regularly placed in
quincunx ; on the exterior they are very irregularly disposed, larger
and less numerous.
The rimule of the peristomice is very irregular. In reality the
form of the apertura belongs to the group of very typical Schizoporella
and the operculum ought to be chitinized enough to insure
sufficiently the opening of the compensatrix by itself.
Occurrence.—Claibornian (Gosport) ; Claiborne, Alabama (rare).
One mile west of Rockville, Clarke County, Alabama (rare).
Type.—C?it. No. 62595, U.S.N.M.
METRADOLIUM, new genus.
{Metra, womb ; dolios, deceptive, having reference to the deceptive
aspect of the ovicells.)