Bulletin - United States National Museum - Smithsonian Institution

68 BULLETIN 91, UNITED STATES NATIONAL MUSEUM.
MELANELLA THALIA, new species.
Plate 19, fig. 9.
Shell small, elongate-conic, very slightly falcate, bluish white;
translucent. The whorls are very gently rounded; appressed at the
summit, through which the preceding whorl shines, which gives the
shell the appearance of having a double suture. Suture scarcely
marked. Periphery of the last whorl slightly inflated. Base moderately
long, well rounded; entire surface marked by exceedingly
fine lines of growth, and an occasional inconspicuous varix. Aperture
oval; posterior angle acute; outer lip clavate; inner lip very oblique,
slender, strongly curved and decidedly reflected, free; parietal wall
covered with a moderately thick callus.
The type and two other specimens, Cat. No. 187078, U.S.N.M.,
come from Port Alfred (Coll. No. 619). The type has eight whorls,
and measures: Length, 3.2 mm.; diameter, 1.1 mm.
MELANELLA ASSER, new species.
Plate 25, fig. 7.
Shell very minute, bluish white; transparent; not falcate. Whorls
almost flattened; appressed at the summit, through which the pre-
ceding whorl shines, which lends the shell the aspect of having a
double suture. Suture scarcely perceptible. Periphery of the last
whorl well rounded. Base moderately long, well rounded; entire
surface of spire and base marked by exceedingly fine, incremental
lines. No varicial markings are apparent on any of our shells.
Aperture oval, posterior angle acute; outer lip 'clavate; inner lip
short, curved, slightly reflected; parietal wall covered by a moder-
ately thick callus.
The type and two specimens, Cat. No. 187079, U.S.N.M., come
from Port Alfred (Coll. No. 620). The type has five and one-half
whorls, and measures: Length, 1.7 mm.; diameter, 0.7 mm.
Cat. No. 250382, U.S.N.M., contains another specimen from the
same locality .(Coll. No. 1255).
MELANELLA, species?
Cat. No. 250385, U.S.N.M., contains the tip of a large, straight
species from Port Alfred, differing from any of those I have seen
from South Africa (Coll. No. 1258).
MELANELLA ACRIFA, new species.
Plate 20, fig. 8.
Shell large, regularly elongate-conic, thin. Nuclear whorls two,
well rounded, forming a somewhat bulbous apex. Postnuclear turns
well rounded, appressed at the summit, the appressed portion ap-
pearing as a slender thread; entire surface marked by almost -vertical,
somewhat sinuous, strongly curved fines of growth. Sutures strongly