Type species: Cancilla isabella (Swainson, 1840).
The shells of the genus are small to moderately large, 20.0-120.0 mm in length, elongate-fusiform, whorls convex or flat-sided, protoconch conical and consisting of 2-3.5 smooth, glassy embryonic whorls. Sculpture consists of spiral cords which vary from thread-like to almost flat, the interspaces are narrow or broad and ornamented with numerous longitudinal striae. The aperture is narrow, shorter or longer than the spire and smooth within, outer lip convex and undulate, columella with 3-6 oblique folds, siphonal canal straight or recurved, siphonal notch distinct. Periostracum thin and brown in color or black and opaque.
The radula of the type species Cancilla isabella is still unknown but shells of the genus are sufficiently characteristic to be considered to belong to a small, compact group. Species of Cancilla made their appearance during Miocene times in Europe and during the Pliocene were already living in Japan and Taiwan. Recent species live in W. Africa, the E. coast of South America and the Philippine-Japanese region. The group contains 4 living species and 36 fossil "species" from the European Tertiary. The record of a Cancilla species from Upper Eocene deposits of Egypt (Abbass, 1967) is questionable.
Some authors use Tiara Swainson, 1831, for this group, but Gray's (1847) designation of Voluta rugosa Gmelin, 1791, as type species of Tiara makes this genus a synonym of Vexillum Roding, 1798, family Costellariidae.