Descriptions of this species were provided by VERDUIN (1984) and SEGERS ET AL. (2009). Shell ovoid, not exceeding 1.2 mm x 0.6 mm. The body whorl encompasses about 80% of the height and aperture nearly 50%. Three very basal furrows delimit weak cords, wider than the interspaces. There is a mild subsutural rim. Several negligible striae can be seen at high magnification in the subsutural area. The colour of the shells is characteristic, being chestnut brown (including the inner lip) with two wide whitish stripes on the body whorl, one at the base and the other in the middle zone.
Paucispiral protoconch of about 1.4 whorls and 250 µm in diameter (nucleus 70 µm). Its sculpture consists of seven or eight equally spaced spiral grooves.

C. perminima has been confused with C. spadix (see remarks under that species) since VERDUIN (1988) suggested that the latter taxon could be a junior synonym of the former. TISSELLI & GIUNCHI (2005) recorded this species in Sardinia (western Mediterranean Sea) and considered the possibility that the species was introduced by shipping. These Mediterranean shells are slightly larger than those of C. perminima from Canary Islands (1.4 mm vs. 1.2 mm), their whorls are more convex and the reddish-brown colour of the inner lip cannot be seen. This is why we think that the Mediterranean specimens may belong to another species.

Madeira, Selvagens and Canary islands, mainly in shallow waters.