There are 5-6 whorls which sometimes appear inflated below the sutures and impart some irregularity to the profile of the spire; the last whorl, with about 24 spiral ridges, may be a little keeled. The upper colour marks are opisthocline, the lower ones prosocline. A minute umbilical crack occurs in some shells. Up to 3 mm high, 1.5 mm broad; last whorl occupies about two thirds of shell height, aperture less than half.
The animal has a rather short snout and the tentacles are flattened. There is a short pallial tentacle on the left edge of the mantle skirt and a longer one on the right. The metapodial tentacle has three points. The flesh is cream in colour and there are yellow blotches, one behind each eye, others under the operculum.
C. semistriata occurs on the lower parts of rocky shores throughout the British Isles; not uncommon in the south, it becomes less frequent in the north. The animals seem gregarious and cluster in the base of algal tufts, under stones and in rock pools in the lower half of the beach and sublittorally. They seem to prefer silty places and are detritivores. Their recognition as a species of Alvania (now Crisilla) rather than Cingula is due to Ponder (1985).
Breeding (at Plymouth) occurs March-August when transparent, hemispherical capsules are laid in groups on the weeds amongst which the adults live. Each capsule has a diameter of 600 µm and contains 12-22 eggs which develop to veliger larvae.

Because it is a common and well-known species on European coasts, it has been described in several publications (FRETTER & GRAHAM, 1978; VERDUIN, 1984; GRAHAM, 1988; GOFAS & OLIVER, 2011; SCAPERROTTA, BARTOLINI & BOGI, 2011). The description that follows is based on the material studied by us.
Shell oval-conic, opaque and not shiny when the periostracum is intact, but translucent when lacks of it. The adults with about 4 spiral whorls reach 2.5 mm in height and 1.3 mm in width. Profile of the spire from flat to flat-convex with suture scarcely deep but, due the salience of the supra and infrasutural cords, presents a slightly canaliculated appearance under high magnification. The ornamentation is formed by spiral cords and furrows crossed by growth lines and close-set weak ribs, which can be observed between the furrows under high magnification, giving a reticulate appearance to well preserved shells. In some shells, the cords placed in the middle of the spire are more obsolete or may even be absent. There is no umbilicus but the internal lip can be extended over a small sulcus. The external lip is not usually thick¬ened, except in larger shells, some of them with a slight varix. None of the studied shells had an internal dentition of the external lip. Background colour of the shell yellowish-white or red-brownish when the periostracum is present. There are two spiral rows of red-brownish blotches. The spots of the upper band can have a shape from rectangular to arrowhead, and those of the lower band is divided in two on the body whorl. The colour is more whitish than on the rest of the shell on the basal part. The external soft parts were described by JEFFREYS (1867); FRETTER & GRAHAM (1978), LUQUE (1984) and PONDER (1985) who provided some anatomical data. Protoconch multispiral, with a little more than 2 whorls and 370 µm in width. Embryonic protoconch (protoconch I) ornamented with 5 fine longitudinal slightly sinuous lines, separated by some small papillae. The rest of the protoconch presents small granules grouped near the suture forming microcordlets. Details of the protoconch can also be seen in THIRIOT-QUIEVREUX & RODRIGUEZ BABIO (1975).
Some shells from Chafarinas Islands resemble those of C. transitoria having an incipient axial sculpture and more cyrtoconoid profile but lack internal folds in the outer lip, present in the African species, and the protoconch also presents some differences.

Shell ovato-conic in form, solid, semitransparent, whorls convex, suture incised. Last whorl is about 70% of total height, aperture about 45%. Sculpture, present all over surface, is made by spiral striae alternate with fine grooves crossed by growth lines so to look like a sculpture finely reticulated. In the subsutural zone it is present one groove broader, while other grooves more evident can be visible at the periphery and at the base. Aperture oval in form, external lip simple, columella arched and umbilicus variable, generally just sketched. Colour is made by 2-3 series of spots light brown in colour, spirally aligned, on a ground white yellowish in colour. As far as fresch specimens are concerned, it is present a periostracum slight, semitransparent. Apex sharp, protoconch has a spiral ornamentation fine and soft. This species is easily recognizable from its similar ones due to its sculpture and to its chromatic pattern. Average measures of adult specimens are around 1.5-2 mm in height.

Throughout the Mediterranean (less frequent on the eastern basin according to BITLIS & OZTURK, 2016) and East Atlantic from Morocco northwards to Southern Scandinavia. The southern limit of its distribution is not known exactly. Although it has been mentioned in some Macaronesian islands (probably due to misidentifications) its presence in the islands has not been verified. It is a frequent species in shallow waters, although some shells have been recorded down to 100 m depth in the Atlantic.

Habitat: it lives in the infralittoral and circalittoral zones. It is found gregarious under rocks and into muddy parts either at the base of
algae or in colonies either of hydrozoans or bryozoans.
Distribution: it is collected all over the Mediterranean. Common enough.