This species has been described in detail by VERDUIN (1984).
The shells studied by us showed some variability. Adult shells somewhat solid, with something more than four whorls, can reach up to 1.7 x 0.85 mm. The last whorl occupies about 70% of the total height, while the aper¬ture exceeds 43%. Sculpture of about eighteen longitudinal cords in the body whorl, wider than their interspaces, being the suprasutural and subsutural more prominent than the rest. On the other hand, the cords in the middle area of the spire are usually less prominent. At high magnification, close lamellae can be observed in the interspaces. Shells translucent with a white-yellowish background colour and a whitish apex and basal area; inner part of the outer lip with a reddish-brown hue by trans¬parency. There are four spiral rows of reddish spots. Paucispiral protoconch with 1.4 whorls, 0.32 mm in diameter and nucleus of 0.11 mm. Ornamentation of coarse granules arranged spirally, grouping progressively to form irregular cords.

SCUDERI & AMATI (2012) pointed out that C. callosa and C. picta are very similar to each other, however both species were well distinguished by VERDUIN (1984), and therefore treated as separated species in the European Register of Marine Species (GOFAS ET AL., 2001). The sculpture of C. callosa is stronger and covers the entire shell, including protoconch (almost smooth in C. picta).

It was found in Tenerife, La Gomera, Gran Canaria and El Hierro Islands (Canaries). NORDSIECK (1972) and NORDSIECK & GARCIA-TALAVERA (1979) mentioned Crisilla callosa in Madeira and Selvagens, but SEGERS ET AL. (2009) exclude its presence in these islands. It is a shallow-water species.