Bulletin - United States National Museum - Smithsonian Institution

SOUTH AFRICAN MARINE MOLLUSKS. 121
Family LITIOPIDAE.
Genus ALABA A. Adams.
ALABA PINNAE Krauss.
There are three lots of this species in the United States National
Museum, all from Port Alfred. Cat. No. 186813, seven specimens
Coll. No. 179). Cat. No. 187052, eight specimens (Coll. No. 590).
Cat. No. 250413, one specimen (Coll. No. 1286).
Genus ALABINA Dall.
ALABINA ALFREDENSIS, new species.
Plate 5, fig. 7.
Shell elongate-conic, white. Nuclear whorls about two and one-
half, smooth, well rounded. Postnu clear whorls with a strong
sloping shoulder which extends over the posterior half of the whorls
and is bounded anteriorly by a median spiral keel. A second keel, a
little less strong than the median, occupies the space halfway between
the suture and the median keel. In addition to the above sculpture
the whorls are marked on the anterior half, between the sutures, by
ill-defined axial ribs which lend the two keels a slightly tuberculated
appearance. About twelve of these feeble tubercles occur upon the
antipenultimate whorls. Periphery and base of the last whorl well
rounded, the latter smooth, excepting feeble lines of growth. Aperture
moderately large; outer lip thin; columella slightly curved and
feebly revolute; parietal wall glazed with a thin callus.
The type, Cat. No. 187053, U.S.N.M., comes from Port Alfred (Coll.
No. 591). It has nine and one-half post-nuclear whorls, and measures:
Length, 3.2 mm.; diameter, 1.2 mm.
ALABINA AFRICANA, new species.
Plate 12, fig. 1.
Shell small, elongate-conic, semitransparent, white. Nuclear
whorls one and a half, well rounded, separated by a strongly con-
stricted suture, and marked by four strong, equal and equally spaced,
spiral keels. Postnuclear whorls well rounded, marked by almost
vertical, well rounded, quite regular, axial ribs, of winch 14 occur upon
the first and second, 16 upon the third and fourth, 18 upon the fifth
and the penultimate turn. In addition to the axial ribs, the whorls
are marked by two spiral cords a little anterior and posterior to the
middle of the space between the sutures. The junction of the axial
ribs and the spiral cords forms tubercles, which are truncated posteriorly
and slope gently anteriorly, while the spaces inclosed between
them appear as well impressed pits. Sutures strongly constricted.
Periphery of the last whorl marked by a strong, smooth, spiral cord.
Base short, slightly concave, smooth. Aperture subcircular; pos-