Bulletin - United States National Museum - Smithsonian Institution

SOUTH AFRICAN MARINE MOLLUSKS. 153
specimens (Coll. No. 1362); Cat. No. 250490, four specimens (Coll.
No. 1363); Cat. No. 250492, four young specimens (Coll. No. 1365);
Cat. No. 250493, one specimen (Coll. No. 1366); Cat. No. 250494,
one specimen (Coll. No. 1367); Cat. No. 250496, four young specimens
(Coll. No. 1369).
OXYSTELE TABULARIS Krauss.
Cat. No. 113a, U.S.N.M., one specimen collected by William Stimpson
on the North Pacific Exploring Expedition at the Cape of Good
Hope. Cat. No. 31697, U.S.N.M., five specimens from the Cape of
Good Hope. Cat. No. 98009, U.S.N.M., five specimens from Kassouga,
South Africa. Cat. No. 186879, U.S.N.M., three specimens
from Port Alfred (Coll. No. 249).
Genus UMBONIUM Link.
UMBONIUM VESTIARIUM Linnaeus.
Cat. No. 59857, U.S.N.M., contains twelve specimens from the
Cape of Good Hope.
Genus GIBBULA Risso.
GIBBULA LOCULOSA Gould.
Plate 23,figs. 1, 2, 3.
Gibbula loculosa Gould, Proc. Bost. Soc. Nat. Hist., vol. 8, p. 21, 1861.
Shell helicoid, light brown, with three large white spots between
the suture and the periphery of each whorl, dividing the whorl into
equal areas. There are also small spots darker than the general
coloration which are especially apparent on the strong spiral cords
which they divide into equal alternating light and dark areas. These
small markings give the base a checker-board appearance. Nuclear
whorls small, well rounded, the first smooth, the second provided with
four feeble spiral threads. Postnuclear whorls marked by strong
sublamellar spiral keels, of which four occur upon the first, and five
upon the second. On the next turn an intercalated cord occurs
between all the strong keels excepting the space between the third
and fourth which has two. On the last turn two cords occur between
the first and second keels, one between the second and third, three
between the third and fourth and fourth and fifth. In addition to
the spiral sculpture the whorJs are marked on the spire by numerous
closely spaced, decidedly retractively slanting, thin, lamellar, axial
riblets. Suture strongly impressed. Periphery rendered strongly
angulated by a spiral keel, between which and the first supraperiph-
eral keel two slender cords are presented. Base well rounded, narrowly
umbilicated, marked by a series of more or less regularly alternating
strong and less strong spiral cords of which there are twenty-