SOUTH AFRICAN MARINE MOLLUSKS. 25 



tional cords, which equal those between the sutures in strength and 

 have about the same spacing. The spaces between these spiral cords 

 are about as wide as the cords. In addition to the spiral cords, the 

 whorls are marked by slender axial ribs, which are slightly pro- 

 tractive. Of these ribs, 12 occur upon the first, 16 upon the second 

 and 28 upon the last turn. The junctions of the axial ribs with the 

 spiral cords form slender tubercles, while the spaces enclosed between 

 them appear as well rounded, strongly impressed pits. On the 

 anterior half of the base, the axial riblets become much enfeebled, so 

 that here the pitting is less apparent. Sutures strongly constricted; 

 aperture moderately large, decidedly channeled posteriorly and ante- 

 riorly; outer lip thin, showing the external sculpture within. The 

 inner edge of the columella and the parietal wall is covered with a 

 thin callus. 



The type and two specimens of this species, Cat. No. 249730, 

 U.S.N.M., come from Port Alfred (Coll. No. 1002). The type has four 

 postnuclear whorls and measures: Length, 3.1 mm. ; diameter, 1 .4 mm. 



MANGILIA CONSANGUINEA Sowerby. 



Cat. No. 249747, U.S.N.M., contains one specimen from Port 

 Alfred (Coll. No. 1019). This species was described by Sowerby as 

 Columbella consanguinea, but we believe that it belongs to Mangilia. 



MANGILIA NISGA, new species. 

 Plate 7, fig. 1. 



Shell small, yellowish white. Nuclear whorls small, one and a half, 

 smooth, forming a very small, well-rounded, white apex. Post- 

 nuclear whorls with a very strong sloping shoulder, which is bounded 

 anteriorly by a strong tuberculated spiral cord. In addition to this 

 cord, the whorls are marked by three additional cords, which decrease 

 in strength successively from the strong cord at the shoulder, to the 

 suture. The space between the strong shoulder and the summit of 

 the shell is marked by a strong spiral thread. Base of the last whorl 

 marked by a peripheral cord, about as strong as the one adjacent to 

 it posteriorly and two others as strong as this, having the same spac- 

 ing as those on the spire. The columella is provided with four cords, 

 of which the fourth, which marks the anterior limit of the columella, 

 is as strong as the first, while the two intermediate ones are less 

 strongly developed. In addition to the spiral sculpture, the whorls 

 are marked with rounded, low, quite regularly spaced, axial ribs, 

 of which 10 occur upon the first and second, and 14 upon the last 

 turn. These ribs render the spiral cords tuberculated at their junc- 

 tion with them. In addition, to these strong axial ribs, the entire 

 surface of the shell, between the sutures ami the anterior half of the 



