SOUTH AFEICAN JUAEINE MOLLUSKS. 127 



Two additional lots, both from Port Alfred, are in the collection of 

 the United States National Museum. Cat. No. 250416, one specimen 

 (Coll. No. 1289), the other Cat. No. 250417, one specimen (Coll. No. 

 1290). 



AMPHITHALAMUS AFRICANUS, new species. 

 Plate 21, fig. 6. 



Shell minute, elongate-conic, semitransparent. Nuclear whorls one 

 and a half, well rounded, smooth. Postnuclear whorls almost three, 

 strongly* rounded, appressed at the summit, marked by numerous, 

 regular, fine, decidedly retractive axial riblets, the spaces between 

 which are about one and a half times as wide as the riblets. Sutures 

 strongly constricted. Periphery of the last whorl well rounded. 

 Base somewhat produced, marked like the spire by the continuations 

 of the riblets. Aperture broadly oval, decidedly oblique; outer lip 

 thin; inner lip strongly curved at some little distance from the parie- 

 tal wall. The space between the inner edge of the outer lip and the 

 parietal wall form a shelf, as is usual in Amphithalamus . 



The type, Cat. No. 250415. U.S.N.M., comes from Port Alfred 

 (Coll. No. 1288). It measures: Length, 1.2 mm.; diameter, 0.5 mm. 



Genus ALVANIA Risso. 



ALVANIA NEMO, new species. 



Plate 5, fig. 3. 



Shell small, elongate-ovate, yellowish white. Nuclear whorls one 

 and one-half, well rounded, smooth. Postnuclear whorls inflated, 

 strongly rounded, marked between the sutures by very regular, well 

 developed, evenly spaced spiral cords, of which four occur upon the 

 second and third, and 6 upon the penultimate turn. The space be- 

 tween the appressed summit and the first spiral cord is a little wider 

 than those between the other cords. In addition to the spiral cords 

 the whorls are marked by feeble incremental lines. Periphery of the 

 last whorl inflated. Base moderately long, well rounded, narrowly 

 umbilicated, marked with two, feeble, spiral cords and fine, incremental 

 lines. Aperture broadly oval; posterior angle obtuse; outer lip thin, 

 showing the external sculpture within; columella strongly curved, 

 free, partly reflected over the umbilicus; parietal wall glazed with a 

 thin callus. 



The type, Cat. No. 187057a, U.S.N.M., comes from Port Alfred 

 (Coll. No. 595). It has almost four postnuclear whorls, and meas- 

 ures: Length, 1.8 mm.; diameter, 1 mm. 



The following four additional lots from Port Alfred are in the col- 

 lection of- the United States National Museum. Cat. No. 250403, 

 two specimens (Coll. No. 1276). Cat. No. 250402, two specimens. 



