Bulletin - United States National Museum - Smithsonian Institution

88 BULLETIN 91, UNITED STATES NATIONAL MUSEUM.
situated at the anterior extremity of the posterior fourth, between
the sutures, while the second is about as far posterior to the suture.
The posterior of these two grooves is bounded posteriorly by a slender
raised cord. In addition to this spiral sculpture the whorls are
marked by numerous fine spiral striations and decidedly retractive
lines of growth. The latter assume somewhat the appearance of feeble
riblets between the slender cord and the summit. Sutures strongly
constricted. Periphery of the last whorl well rounded. Base mod-
erately long, well rounded, with a very fine umbilical perforation;
marked by the continuation of the lines of growth and numerous fine
spiral striations, which are a little stronger than those on the spire.
Aperture broadly oval; posterior angle very obtuse; outer lip very
oblique, thin; inner lip very strongly curved and appressed to the
preceding turn; except the extreme anterior portion, which is free;
parietal wall glazed with a thin callus.
The type, Cat. No. 250391, U.S.N.M., comes from Port Alfred (Coll.
No. 1264), has four postnuclear turns, and measures: Length, 1.5 mm.;
diameter, 0.7 mm.
ODOSTOMIA (MENESTHO) RIFACA, new species.
Plate 18, fig. 3.
Shell very elongate-ovate, milk white. Nuclear whorls well
rounded, smooth, immersed in the first of the succeeding turns, above
which the tilted edge of the last volution only projects. Postnuclear
whorls moderately rounded, having a strongly impressed spiral groove
a little below the summit, which causes this to appear as a wellrounded
spiral cord. The rest of the surface between the sutures is
marked by numerous very fine spiral lirations, and exceedingly fine
axial lines of growth. Sutures strongly constricted. Periphery of the
last whorl somewhat inflated, well rounded. Base slightly atten-
uated, very narrowly umbilicated, well rounded, marked by the con-
tinuation of the lines of growth and spiral lirations which equal those
of the spire in strength and spacing. Aperture irregularly ovate;
posterior angle acute; outer lip thin, oblique; inner lip decidedly
curved, reflected over and appressed to the preceding turn, the extreme
anterior tip only being free. A strong oblique fold marks the
insertion of the columella. Parietal wall glazed by a thin callus.
The type, Cat. No. 250365, U.S.N.M., comes from Port Alfred (Coll.
No. 1238). It has five postnuclear whorls, and measures: Length,
1 .9 mm. ; diameter, 0.9 mm.
ODOSTOMIA (MENESTHO) FICARA, new species.
Plate 16, fig. 1.
Shell broadly elongate-conic, rather thick, bluish white, Nuclear
whorls small, deeply, obliquely immersed in the first of the postnuclear
turns, above which a part of the last two volutions project. Postnu-