Bulletin - United States National Museum - Smithsonian Institution
Bulletin - United States National Museum - Smithsonian Institution
Bulletin - United States National Museum - Smithsonian Institution
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
EARLY T1^,P>TIAITY CHEILOSTOME ERYOZOA. 53<br />
CYSTISELLA, new genus.<br />
{Cystis, bladder, pouch.)<br />
The frontal is an olocyst. It bears a very wide avicularian chamber<br />
in Avhich there is a pair of large glands. The mandibles have<br />
a liicida in the middle. (Waters).<br />
Genotyi>e.— Cystlsella {Por^ella) saccata P)iisk,<br />
Range.—Midwayan-Recent.<br />
1856.<br />
" In Porella saccata it [the ovicell] is many-layered, as thin cal-<br />
careous layers, presumably gymnocyst [our olocyst] layers, con-<br />
tinually grovv^ over the 0(£cium, not only from the distal zooecium<br />
but also from the two neighboring zocecia, and w^e can see, as a rule,<br />
three, distinctly separated, thin covering plates on their surface." ^<br />
CYSTISELLA MIDWAYANICA. new species.<br />
Plate 5, fig. G.<br />
Description.—The zoarium incrusts shells. The zooecia are dis-<br />
tinct, somewhat elongated, hexagonal, separated by a furrow or a<br />
thin salient thread ; the frontal is very convex and very finely granu-<br />
lated. The peristome is thin, little salient in its distal part ; it bears<br />
some spines; the peristomice is elliptical and deformed inferiorly by<br />
the avicularium. The aviculariam forms a long chamber, median<br />
and conical; its orifice is little circular and turned toward the<br />
apertura.<br />
MeasureTThents.—Peristomice *<br />
/ a\ i<br />
l/pe=0.14mm.<br />
• rj fZs=0.40 mm.<br />
Zooecia , ^ ^^<br />
1 fe=0.30mm.<br />
Occurance.—Midyvaynn (Clayton limestone) : Luverne, Crenshaw<br />
County, Alabama (very rare).<br />
One mile west of Fort Gaines, Georgia (rare).<br />
Type.—Cat. No. G2902, U.S.N.M.<br />
Genus PORELLA Gray, 1848.<br />
1848. Porella Gray, List of British Animals in collection British <strong>Museum</strong>.<br />
Centrouiae, pp. 127, 148.<br />
The ovicell opens into the peristomie; it is porous, imbedded in<br />
the distal zocecium. The apertura is semilunar. Neither lyrule nor<br />
cardelles. The operculum is almost straight in its proximal part,<br />
with rounded corners; there is a muscular prominence a little dis-<br />
tance from the edge. In front of the apertura there is an avicularium<br />
; the mandible is semicircular and has well-marked thickenings<br />
1 Leviasen, JHorp'aological and Systematic Studies on the Cheilostomatous Bryozoa, p. 336.