Bulletin - United States National Museum - Smithsonian Institution

SOUTH AFRICAN MARINE MOLLUSKS. 159
bands which have the same arrangement as the spiral sculpture on
the spire. The umbilicus is without any sculpture. Entire surface
of spire and base marked by exceedingly fine lines of growth which are
decidedly retractively slanted on the spire. Aperture subquadrate,
decidedly oblique; outer and basal lips forming an obtuse angle at
their junction; inner lip thick, decidedly sinuous; parietal wall
glazed with a thin callus.
The type, Cat. No. 102730, U.S.N.M., comes from the Cape of Good
Hope. It has four postnuclear whorls, and measures: Altitude,
6 mm.; greater diameter, 6.4 mm. Cat. No. 43011a, U.S.N.M., contains
one specimen from the Cape of Good Hope.
GIBBULA MEDUSA, new species.
Plate 29, figs. 7, 8, 9.
Shell depressed conic. Nuclear whorls white. Postnuclear whorls
marked with broad axial bands of brown which ma} T
extend
entirely across the whorls, or may be interrupted in the middle.
These bands of brown are separated by spaces of a light sage green,
which are about as wide as the brown bands on the posterior half of
the whorls between the sutures; the green area fading to yellow
anteriorly. These light areas are speckled with small dots of chestnut
and clouded in places with pale brown. The base is pale green,
profusely spotted with dots and blotches of red. Nuclear whorls two
and a quarter, depressed helicoid. Postnuclear whorls evenly
rounded, marked with two, broad, spiral bands, which extend over the
anterior half of the whorls between the sutures, where they appear
as two turns of a bandage. The periphery of the last whorl is marked
by a moderately strong spiral keel which renders it angulated.
Sutures feebly constricted. Base short, well rounded, broadly
umbilicated; marked by seven broad low bands which grow successively
wider from the umbilical edge toward the periphery. These
bands appear as a series of turns of a bandage. Umbilicus
without any spiral sculpture. The entire surface of spire and base
is marked with faint retractive lines of growth. Aperture very
oblique, oval ; outer and basal lips thin, showing the external markings
within; inner lip quite thick, evenly curved; parietal wall glazed
with a very thin callus.
The type and two specimens of this species, Cat. No. 43011,
U.S.N.M., come from the Cape of Good Hope. The type has two
and one-half postnuclear whorls, and measures: Altitude, 3.5 mm.;
greater diameter, 5 mm.
GIBBULA TRYONI Pilsbry.
Cat. No. 186873, U.S.N.M., three specimens from Port Alfred
(Coll. No. 243).