Shell small, high spired, about four times as long as wide, of 8-9 whorls. Protoconch tiny, of two and a half smooth whorls. Teleoconch with a sculpture of two high spiral cords, narrower than the interspaces and clustered together; separated from the suture by a sloping surface; on the later whorls a third cord may appear on that subsutural surface; axial folds determine acute knobs at their intersection with the spirals and form with these a characteristic clathrate sculpture. Aperture pyriform, not thickened, with outer lip joining anteriorly the columella with a quite regular curve, not forming a siphonal canal.
brown on the early whorls grading to pale whitish on the body whorl, with the columella usually tinged with brown; some specimens entirely brown.
common size :
3 x 0.9 to 4 x 1.1 mm.
This species could easily be confused with the native Bittium submamillatum (de Rayneval and Ponzi, 1851). C. ferruginea will be distinguished in being less solid, in having only two spirals instead of four on the mid-spire whorls, and in that the spirals on later whorls are more raised and narrower than the interspaces (broader in Bittium). There is much taxonomic uncertainty as to the relationships of small related Indo-Pacific cerithids, the revision of which is out of the scope of the Atlas. C. cerithina (Philippi, 1849) differs in having four spiral cords instead of two on spire whorls; the name used here was suggested by Dr van Aartsen upon examination of the relevant type material.
BIOLOGY / ECOLOGY
Larvae are planktotrophic, ensuring long-distance dispersal.
on soft bottoms, sandy or muddy, in 5-30 m.