Bulletin - United States National Museum - Smithsonian Institution

SOUTH AFRICAN MARINE MOLLUSKS. 113
which the first is at the summit, while the third is about as far above
the suture as it is distant from the cord adjacent to it posteriorly,
median cord being a little nearer than that a little anterior to it. In
addition to the spiral cords the whorls are marked by strong axial
ribs, of which 18 occur upon all the whorls. The intersection of the
spiral cords and the axial ribs, form very strong tubercles, while the
spaces inclosed between them appear as well impressed, oval pits,
the long axis of which coincides with the spiral sculpture. The
tubercles of the cord at the summit are well rounded; those of the
other two cords are truncated anteriorly, sloping posteriorly; those
of the median cord a little less so than those of the suprasutural cord.
Sutures strongly channeled. Periphery of the last whorl marked by
a sulcus which is as strong as that between the median and the supra-
sutural cord and like that crossed by the continuations of the axial
ribs which extend over the cord anteriorly to the peripheral sulcus
and renders this slightly tuberculated. Base marked by two spiral
cords, the first immediately anterior to the peripheral sulcus, the
other one occupying a position half way between this and the tip
of the columella. Columella anterior to the second cord is crossed
by several slender spiral threads. Aperture moderately large, de-
cidedly channeled anteriorly; outer lip rendered sinuous by the
external sculpture; inner edge of the columella covered with a thick
callus which extends over the parietal wall, rendering the peritreme
complete.
The type, Cat. No. 249690, U.S.N.M., comes from Port Alfred
(Coll. No. 962). It has six and a half postnuclear whorls, and measures:
Length, 3.8 mm.; diameter, 1.5 mm.
CERITHIOPSIS, species?
Cat. No. 250356, U.S.N.M., contains a worn specimen from Port
Alfred (Coll. No. 1229). This is different from any we know from
the region, but is too poor to be described.
Genus SEILA A. Adams.
SEILA ALFREDENSIS, new species.
Plate 5, fig. 6.
Shell very elongate-conic, light chestnut brown, maculated with
blotches and spots of white. Nuclear whorls three, smooth, well
rounded, white, forming a bulbous apex, the first turn being the
largest. Postnuclear whorls moderately rounded, ornamented with
four strong, flattened, subequal and subequally spaced spiral cords,
of which the first is at the shouldered summit, while the anterior
portion of the last abuts the summit of the succeeding whorls. The
spaces inclosed between these cords are about as wide as the cords