The shell is very similar to that of C. perminima, pupoid with somewhat more than 3 whorls and up to 1.1 x 0.58 mm. The last whorl and aperture are large. There are three very weak basal furrows that delimit cords, also weak, somewhat wider than the interspaces. The subsutural rim is conspicuous. Some negligible subsutural striae can be observed at high magnification. Whitish shell with discontinuous and wide, poorly defined reddish bands, one subsutural and the other two very close together. Umbilical area and inner lip reddish brown.
Paucispiral protoconch with 1.25 whorls and about 270 µm in diameter (nucleus around 90 µm). Sculpture of about eight equidistant cordlets which delimit flat spiral bands of similar width.

As previously stated, this species has been confused with C. perminima (see remarks in this species) and VERDUIN (1988) and SEGERS ET AL. (2009) considered both taxa as synonyms. However, both species are distinguished by the sculpture of their protoconchs (spiral grooves in C. perminima, spiral cords in C. spadix) and details of their colour pattern. As an example, PALAZZI (1988, fig. 5) erroneously illustrated a protoconch of C. spadix as C. perminima.

Madeira and Selvagens Islands, subtidal.