Bulletin - United States National Museum - Smithsonian Institution

182 BULLETIN 91, UNITED STATES NATIONAL MUSEUM.
Genus ARCA Lamarck.
ARCA ACUMINATA Krauss.
Cat. No. 187158, U.S.N.M., one specimen from Port Alfred (Coll.
No. 705).
Genus FOSSULARCA Cossmann.
FOSSULARCA GIBBA Krauss.
Cat. No. 186921, U.S.N.M., one specimen from Port Alfred (Coll.
No. 291).
FOSSULARCA GRADATA Broderip and Sowerby.
Cat. No. 187155, U.S.N.M., contains one specimen and three valves
of this species from Port Alfred (Coll. No. 702).
Genus BARBATIA (Gray) Adams.
BARBATIA ALFREDENSIS, new species.
Plate 46, figs. 9, 10.
Shell rhomboidal. Surface covered with a thick, dark brown epidermis
from which project numerous imbricating scales. The
umbones are situated in the anterior third of the entire length of the
shell. The hinge line is very slightly arcuated, the ventral margin
usually incurved. Anterior end much narrower than the broad
posterior end. Entire surface marked with numerous fine radiating
riblets which are crossed by concentric lines of growth rendering the
sculpture of the surface somewhat reticulated. The interior of the
shell is bluish white, excepting that portion which lies dorsal and
posterior to a hue passing from the umbones to the posterior ventral
margin, which is chestnut brown.
The type and three specimens, Cat. No. 186922, U.S.N.M., come
from Port Alfred (Coll. No. 292). The type measures: Length, 34
mm.; height, 18 mm.; thickness, 12.5 mm.
This is what has probably been listed as Area obliquata Gray, a
Philippine Island species, which differs from the present species by
its much larger size, detailed sculpture, and color.
BARBATIA, species?
Cat. No. 18804, U.S.N.M., contains a specimen from Natal which
we are unable to refer to any of the known species, but which is too
poor to serve for a diagnosis.
BARBATIA, species?
Cat. No. 187157, U.S.N.M., contains six valves of a Barbatia from
Port Alfred, which we are unable to refer to any of the described
species, but is too poor to serve for a diagnosis (Coll. No. 704). Cat.
No. 249850, U.S.N.M., contains six additional valves of the same
species, in the same condition, from the same place (Coll. No. 1122).