Cerithiopsis Forbes & Hanley, 1850 (Type species: Cerithiopsis tubercularis (Montagu, 1803) from Europe), includes species with a high teleoconch, with numerous whorls, not constricted at base, and with a protoconch made of 3 to 6 smooth whorls that is without cords or ribs, sometimes granulose, especially on the first whorl.

Genus Cerithiopsis Forbes & Hanley, 1850 Type species: Cerithiopsis tubercularis (Montagu, 1803), Europe: elongate shell, not constricted at base, with 3 beaded spiral cords per teleoconch whorl, protoconch smooth or punctate, without any axial rib or spiral cord, except sometimes for a spiral carina on last half-whorl.

Animal with a narrow foot, subtruncated in front and attenuated behind, with a longitudinal sulcus on the sole; tentacles cylindrical, the eyes sessile at their base ; opercular lobe simple, well developed. Radula with an oval central tooth, its margin dentate, a large bicuspid lateral tooth, and unictispid marginals with smooth margins.
Shell small, thin, cylindro-conic, narrow ; protoconch polygyrate, with a slightly deviated nucleus ; whorls numerous, tuberculate, not varicose, the last narrower in proportion ; aperture small, sub-quadrangular, with a short, truncate, nearly straight canal ; outer lip thin, not produced at the base ; columella smooth, straight, not twisted below, but simply inflexed towards the basal notch.
Distribution.—Mostly occurring in northern and temperate seas.
Fossil.—Cretaceons.

For the diagnosis of the genus Cerithiopsis see Cecalupo & Robba (2010): substantially the protoconch has a planctotrophic larval development, it is conical with 4.5 convex and smooth whorls. The species reported from the Caribbean as Cerithiopsis show mainly 2 types of protoconch: one conical and smooth, corresponding to the description of the genus, the second, conical with a sculptured suture, not corresponding to the description of the genus. In this second type of protoconch a certain varia- bility of the sculpture has been noted. The spiral above the suture varies from thin and smooth to slightly larger composed by granular microprotuber- ances, and the axial riblets of the band under the su- ture, from more thin and numerous to more sparse and coarser. These variations can be considered as 'extreme' comparing the overall variability of the protoconches within the family , This type of protoconch is common in various species that have been differentiated according to the characteristics of the teleoconch (shape, size and color) pending more detailed studies of the soft parts. At the moment we tend to keep these species in the genus Cerithiopsis (as done by other authors) separating them into three distinct groups: protoconch smooth, protoconch sculptured, while the third group contains species with different protoconches attributable to genera not yet established.