Bulletin - United States National Museum - Smithsonian Institution

SOUTH AFRICAN MARINE MOLLUSKS. 199
BORNIA ARFICA, new species.
Plate 41, fig. 7; plate 51, fig. 4.
Shell broadly oval. Umbones decidedly anterior to the middle.
Outer surface of the shell marked by numerous very closely spaced,
fine, concentric threads, which are a little broader than the spaces
that separate them, and numerous, very fine, microscopic, radiating
striations. The character of the hinge is shown in our detailed sketch.
The type, Cat. No. 2498946, U.S.N.M., comes from Port Alfred
(Coll. No. 11 666). It consists of a right valve, and measures: Altitude,
2.3 mm.; length, 2.8 mm.
BORNIA (PYTHINA) ROTUNDATA Deshayes.
Plate 51, figs. 5, 6.
Cat. No. 186969, U.S.N.M., contains two and one-half specimens
of this species from Port Alfred (Coll. No. 342).
BORNIA (PYTHINA) AFRICANA, new species.
Plate 42, figs. 1, 2; plate 51, fig. 3.
Shell rather large, oval, slightly emarginate at the base, with the
umbones decidedly posterior to the middle. The outer surface is
marked by fine lines of growth and minute tubercles, which lend it a
shagreened appearance. On the anterior end the shell has a few, ill-
defined, raised, radiating threads.
The type and another valve, Cat. No. 187190, U.S.N.M., come from
Port Alfred (Coll. No. 741). The type measures: Altitude, 9.5 mm.;
length, 13.8 mm.
Three additional lots are in the collection of the United States
National Museum, all from Port Alfred, as follows: Cat. No. 251011,
a young specimen (Coll. No. 1528); Cat. No. 251038, one valve (Coll.
No. 1555); Cat. No. 251056, one young valve (Coll. No. 1573).
Genus ROCHEFORTIA Velain.
ROCHEFORTIA CONVEXA Gould.
Plate 45, figs. 1,2; plate 47, fig. 4, young; plate 51, figs. 7, 8, hinge.
Kellia conveza Gould, Proc. Bost. Soc. Nat. Hist., vol. 8, p. 34, 1861.
Shell of suboval outline, wax yellow. Umbones almost median,
with the dorsal margin slanting almost equally, anteriorly and pos-
teriorly. Both ends equally rounded, and the basal margin gently
curved. Entire surface marked by rather irregular, fine lines of
growth. Hinge as shown in Plate 51, figs. 7, 8.
Gould's cotypes, Cat. No. 24244, U.S.N.M., two specimens, were
collected by William Stimpson on the North Pacific Exploring Expe-