Common Name

"Onion Cone"

Status

Regarded as a valid species.

Type Locality

Cabenda, East coast of Africa

Distribution

Endemic to the coast of Angola

Maximum Reported Size

25 mm

Description

The shell is small.and moderately light, the last whorl broadly and ventricosely conical to pyriform, shoulder rounded. Outline convex at adapical third, almost straight below. Spire low to moderately high, outline straight to sigmoid. Sutural ramps flat to convex with fine spiral striae. Last whorl almost smooth, with about 10 spiral ribs near base. Ground color of the shell is white to bluish-white, with dark brown axial streaks, of variable width, occasionally converging at base and shoulder. Light colored aperture.

Radula: mid-sized tooth, of vermivorous type. The apical portion is shorter than half the length of the radular tooth. Denticles coarser in the upper portion of the serration, usually starting within a single row, then split in two; smaller teeth in a single row in the lower portion.

Habitat & Habits

Soft mud, 5 fathoms.

Discussion

C. zebroides is the species most similar to C. bulbus because of the presence of dark axial streaks on the shell, and in fact some specimens can hardly be seperated between the two species, except for the fact that C. zebroides reaches quite larger size. The two species are seperated in terms of the radular teeth. C. bulbus can also be distinguished from C. africanus because of radular morphology and also by the pattern on the shell. C. bulbus can also be seperated from C.variegatus on the same grounds. There are no significant differences in radular morphology between C. bulbus and C. bulbus but specific seperation is accepted on the basis of geographical distribution of the typical forms for each species.

References

• Conch. Icon. 1 (Conus): pl. 30, sp. 169 (1844, Proc. Zool. Soc. London pt. 11, no. 130: p. 171, not figured.