Shell small, slender, whorls flat-sided with three strong cords, and dark brown at first sight. The protoconch has two and a quarter whorls, sometimes a little more, attaining in some specimens two and a half whorls. It is not very wide (0,3 mm), totally smooth and light in colour. The suture is deep and, below it there is a shallow channel on the upper part of the whorl. The protoconch is continued by the teleoconch, beginning with three cords simultaneously, the upper one being thinner. Teleoconch with 7 to 10 whorls of uniform brown colour, sometimes with lighter blotches. The whorls are flat and slowly increasing in size; the suture is imperceptible. Three smooth spiral cords run all over the shell and they are practically equal in size. From the second or the third whorl forward appears a fourth cord, situated immediatly near the suture and smaller than the preceding ones. The interspaces between these cords are also similar and small axial striae a little separated can be seen. On the last whorl are five cords. The base is smooth. The aperture is rectangular with a sharp external edge, and it is undulating with the extremity of the spiral cords. The siphonal canal is open and short. Dimensions: Because most of the specimens studied were incomplete or not totally developed, the real dimensions of the species can only be approximated. The biggest fragments studied have a maximum dimension of 8 mm.

S. adamsi is different because its protoconch is smaller, less elevated, and its nucleus is less promi¬nent, presenting an initial differentiated area; also it lacks the subsutural excavation on the protoconch. S. trilineata has a smaller protoconch with a stria in the suture and lacks die subsutural excavation; moreover, in the teleoconch there is a fourth small cord near the suture. S. carinata has a protoconch with more whorls and the spiral cords of the teleoconch and their interspaces are different. S. angolensis n. sp. is a bigger shell, with spiral cords and different interspaces and its protoconch has more whorls and tubercles in the first one. S.parilis n. sp. has a darker shell and its protoconch has a simple suture and many tubercles on die first whorl.

Type locality: Boavista Island (Cape Verde Archipelago). Some fragments have been collected in sediments dredged in Porto Mindelo (San Vicente Island), Sal-Rei (Boavista Island) and Rabo de Junco (Sal Island).