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 meas- 

 ures: 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 



