SOUTH AFRICAN- MARINE MOLLUSKS. 147 



threads which are about as wide as the spaces that separate them. 

 Postnuclear whorls marked by four, strong, broad, rounded, spiral 

 cords of which the first is at the summit, while the second is a little 

 nearer the first than it is to the third, the fourth, marking the periph- 

 ery, is about as far from the third as that is from the second. On 

 the last turn two additional slender spiral threads make their appear- 

 ance, one immediately anterior to the second, the other, anterior to the 

 third heavy spiral cord. The cords are marked quite regularly by 

 weak tubercles which are about as long as they are broad and are 

 separated from each other by a space about two-thirds as wide as a 

 tubercle. Sutures deeply channelled. Periphery of the last whorl 

 well rounded. Base short, well rounded, marked by seven strong 

 rounded spiral cords which increase in size from the periphery to the 

 columellar chink. The spaces separating the cords are deep sulci 

 narrower than the cords. The entire surface is marked by closely 

 spaced, very slender, wavy, axial threads. Aperture very oblique, 

 small, outer lip bending strongly anteriorly to join the columella, 

 thin at the edge, where it is rendered wavy by the sculpture, but very 

 thick a little behind the edge; columella short, decidedly revolute; 

 parietal wall covered with a thick callus which completes the peri- 

 treme. 



Cat. No. 24269, U.S.N.M., contains Gould's cotypes, three specimens 

 collected by William Stimpson on the North Pacific Exploring 

 Expedition at Simons Bay, Cape of Good Hope. We have figured 

 the largest of these, which has two and one-fourth postnuclear whorls, 

 and measures: Altitude, 5.5 mm.; greater diameter, 6.5 mm.; lesser 

 diameter, 6.0 mm. 



LEPTOTHYRA AFRICANA, new species. 

 Plate 22, figs. 1, 2, 3. 



Shell with moderately elevated spire. Nuclear whorls white, the 

 rest marked with irregular axial bands of white and reddish brown. 

 Nuclear whorls two, apparently smooth. Postnuclear whorls marked 

 with three strong spiral cords between the sutures ; the first of which 

 is a little below the summit, while the third is a little posterior to the 

 periphery, the second being midway between them. The sulci 

 between the cords are almost two times as wide as the cords. On the 

 last whorl an additional cord appears between the first and second 

 and second and third. In each case this anterior cord is greater than 

 the primary ones and a little nearer to the one posterior than to its 

 anterior neighbor. In addition to the spiral sculpture, the whorls 

 are marked by numerous, fine, retractive, axial threads. Sutures 

 strongly impressed. Periphery of the last whorl marked by a strong 

 spiral cord. Base short, well rounded, marked with four strong, 

 spiral cords which equal the peripheral one in strength and a tumid 



