SOUTH AFRICAN MARINE MOLLUSKS. Ill 



addition to the above sculpture, the spire is marked by exceedingly 

 fine lines of growth and microscopic spiral striations. Sutures 

 channeled. Periphery of the last whorl marked by a spiral sulcus 

 as broad as the one posterior to the suprasutural cord and, like that, 

 crossed by the axial ribs, which terminate at its posterior margin. 

 Base short, marked by two spiral cords which are of equal strength 

 and confined to the posterior half of the base. The anterior half of 

 the base between the last cord and the insertion of the columella is 

 slightly concave in the adolescent shell. Aperture subquadrate, 

 decidedly channeled anteriorly; posterior angle obtuse; outer lip 

 rendered sinuous by the sculpture; columella stout; parietal wall 

 glazed with a thin callus. 



The type and another specimen, Cat. No. 250354, U.S.N.M., come 

 from Port Alfred (Coll. No. 1227). The t}^pe, which is an adolescent 

 specimen, has eight and a half postnuclear whorls and measures: 

 Length, 4.5 mm.; diameter. 1.5 mm. Cat. No. 250357, U.S.N.M., 

 contains another specimen from the same locality (Coll. No. 1230). 



CERITHIOPSIS (CERITHIOPSIS) NINA, new species. 

 Plate 12, fig. 2. 



Shell very small, light chestnut brown. Nuclear whorls smooth, 

 forming the slender, mucronate apex of the shell. Postnuclear whorls 

 slightly shouldered at the summit, moderately rounded, marked by 

 three spiral cords, of which the first is at the summit, the third about 

 as far posterior to the suture as it is separated from its neighbor pos- 

 teriorly. In addition to the spiral sculpture, the whorls are marked 

 by strong axial ribs which equal the spiral sculpture in strength. 

 The junctions of the axial ribs and the spiral cords form tubercules, 

 while the spaces inclosed between them form well impressed, squarish 

 pits. The tubercles of the cord at the summit are slightly truncated 

 posteriorly, and slope gently anteriorly; those of the succeeding two 

 cords are abruptly truncated posteriorly, sloping gently anteriorly. 

 Of the axial ribs, 18 occur upon all the whorls except the penulti- 

 mate, on which there are 20. Sutures moderately constricted. 

 Periphery of the last whorl marked b} r a strong spiral cord, the space 

 between it and the suprasutural cord being crossed by the continua- 

 tion of the axial. ribs which terminate at the posterior edge of the 

 peripheral cord. Base slightly concave, with a spiral cord at the 

 insertion of the columella. Aperture strongly channeled anteriorly, 

 almost circular; outer lip thin; columella covered with a thick callus 

 which is reflected over the parietal wall and connects this with the 

 posterior angle of the aperture, rendering the peristome complete. 



The type and another specimen, Cat. No. 250358, U.S.N.M., come 

 from Port Alfred (Coll. No. 1231). The type has almost five post- 

 nuclear whorls, and measures: Length, 1.9 mm.; diameter, 0.7 mm. 



