Bulletin - United States National Museum - Smithsonian Institution

SOUTH AFRICAN MARINE MOLLUSKS. 29
to the axial ribs, the surface of the shell is marked by numerous, fine
lines of growth. The spiral sculpture consists of well-developed
cords, which are about half as wide as the spaces that separate them.
Of these cords, 4 occur between the sutures on the first turn, 5 upon
the second, 6 upon the third and 7 upon the penultimate whorl.
Base marked by about 15 spiral cords, which equal those on the
spire in strength and spacing. Aperture moderately large; posterior
angle obtuse, scarcely channeled; outer lip thin, rendered slightly
sinuous by the spiral cords on the outside; columella and parietal
wall covered with a thin callus.
The type and another specimen, Cat. No. 249734, U.S.N.M., come
from Port Alfred (Coll. No. 1006). The type has five postnuclear
whorls and measures: Length, 7.4 mm.; diameter, 3.1 mm.
MANGILIA, species?
Cat. No. 250454, U.S.N.M., contains a young specimen from Port
Alfred, which we are unable to identify positively (Coll. No. 1327).
MANGILIA GRAYI Reeve.
Cat. No. 186686, U.S.N.M., five specimens from Port Alfred (Coll.
No. 42). Cat. No. 250468, U.S.N.M., one from the same place (Coll.
No. 1341).
MANGILIA NYMPHA, new species.
Plate 3, fig. 4.
Shell very small and slender, semitransparent, light yellow with
the posterior third between the sutures bright chestnut brown on the
later whorls, while the early ones are white. Nuclear whorls dextral,
1£, helicoid, closely coiled, smooth and polished. Post-nuclear whorls
well rounded with appressed summits, ornamented with protractive,
well rounded, axial ribs, of which 12 occur upon the first, 14 upon
the second, 16 upon the third, and 20 upon the last turn. Intercostal
spaces a little wider than the ribs, crossed by equal and equally spaced
spiral bars which pass up on the sides of the ribs but do not cross them;
of these, seven appear between the sutures. Sutures well impressed.
Periphery of the last whorl rounded. Base attenuated, marked by
the feeble continuations of the axial ribs and spiral lirations which
become dominant on the anterior portion where the ribs disappear,
and these form continuous, raised, spiral threads. There are seven
spiral threads on the base. Outer lip fractured, ver} r thin, showing
the external sculpture within; columella strongly sigmoid, covered b}^
a thin callus which extends up on the parietal wall.
The type, Cat. No. 187009, U.S.N.M., comes from Port Alfred
(Coll. No. 542). It has four post-nuclear whorls and measures:
Length, 3.9 mm.; diameter, 1.5 mm. Cat. No. 250462, U.S.N.M.,
contains another specimen from the same locality (Coll. No. 1335).