Bulletin - United States National Museum - Smithsonian Institution

SOUTH AFRICAN MARINE MOLLUSKS. 77
TURBONILLA (PYRGOLAMPROS) ANGEA, new species.
Plate 9, fig. 3.
Shell elongate-conic, brownish yellow. (Nuclear whorls decollated.)
Postnuclear whorls very slightly rounded, feebly shouldered at the
summit marked by rather broad, low, somewhat protractive axial
ribs, of which 16 occur upon the second, 18 upon the third to fifth;
20 upon the sixth; and 22 upon the penultimate turn. These ribs
are about double the width of the spaces that separate them. In
addition to the ribs, the whorls are marked by exceedingly fine,
microscopic, spiral striations. Periphery of the last whorl well
rounded. Base moderately long, well rounded, crossed by the ver}^
feeble continuations of the axial ribs and exceedingly fine, spiral
striations. Aperture oval; posterior angle acute; outer lip thin;
inner lip very short, slightly revolute and appressed, provided with a
weak fold at its insertion; parietal wall glazed with a thin callus.
The type and another specimen, Cat. No. 186844a, U.S.N.M., come
from Port Alfred (Coll. No. 211). The type has seven and one-half
postnuclear whorls, and measures: Length, 5 mm.; diameter, 1.7 mm.
Cat. No. 250375, U.S.N.M., contains three specimens from the same
locality (Coll. No. 1248).
TURBONILLA (PYRGISCUS) HELENA, new species.
Plate 14, fig. 1.
Shell small, elongate-conic, golden brown. Nuclear whorls, at least
two, forming a depressed helicoid spire which is obliquely immersed
in the first of the succeeding turns, above which a portion of the last
two whorls only projects. Postnuclear whorls strongly, tabulatedly
shouldered at the summit, well rounded, somewhat constricted at the
sutures, marked by very regular, slightly retractive, axial ribs, which
are almost as wide as the spaces that separate them. Of these ribs,
there are about 24 on the first and second, 22 upon the third, 26 upon
the fourth, 30 upon the fifth, and 32 upon the penultimate whorl.
The ribs render the summit of the whorls crenulated. Intercostal
spaces strongly impressed, marked by numerous fine, equal, and
equally spaced, spiral striations, of which about 30 occur between the
sutures on the penultimate turn. Sutures very strongly constricted,
base moderately long, well rounded, marked by the continuations of
the axial ribs, which become enfeebled as they approach the umbilical
chink, and incised, spiral lines equaling those on the spire in spacing
and strength. Aperture oval, posterior angle rendered decidedly
obtuse by the shoulder at the summit. Outer lip thin, showing the
external sculpture within; inner lip strongly curved, reflected over
and appressed to the base, provided with a weak, oblique fold at its
insertion. Parietal wall covered by a thin callus.