This species has a really variable sculpture originating some varieties. Shell conic in form, slim, whorls convex and apex rather flattened. There are present from two to four spiral cords that can form some small nodules at crossing with axial ribs. There are very often present varices lighter in colour. Aperture oval in form with lip simple. At the base there can be present some belts. Siphonal tube missing. Brown in colour, more or less broad, with flammulae lighter in colour. Ecostata form, light beige in colour, is axial ribs missing. Pulchella form is it itself axial ribs missing but it has a larger number of spiral belts (5-6 per whorl) and whorls are more convex than in ecostata form. Moreover pulchella form is recognizable due to its typical dark brown colour as far as protoconch and first whorls of teleconch are concerned, then, in the following whorls, it becomes dirty white in colour. This species is better known as assigned to the genus Cerithidium, but recently (Costello et al., 2001) it has been assigned to the genus Bittium. Average measures of adult specimens are around 5 mm in height.

The species in question can always be distinguished from Bittium reticulatum (Da Costa) s.l. and related forms by the absence of a real siphonal canal (probably the reason why Jeffreys described it originally as Turritella ? and later on changed that generic placement to Mesalia ?), by its rather convex whorls which show 5 spirals on the later ones, by the frequent occurrence of varices and by the difference in embryonic whorls. As to this point it should be mentioned that Richter & Thorson (1975: 129, pl. 4 fig. 20, 21) give a detailed description as well as a very fine picture of the protoconch of Cerithidium submammillatum under the erroneous name of Bittium jadertinum Brusina, 1865. We have been able to check this on the original material, for which we thank Dr. G. Richter, who placed it most kindly at our disposal.

Habitat: it lives on sandy-muddy and coralligenous bottoms in the infralittoral and circalittoral zones. Distribution: It can be found all over the Mediterranean. Ecostata form is more common in the middle Adriatic, while pulchella form is quoted in literature as frequent along the Straits of Gibraltar and, recently, even along the Straits of Messina (Sicily - Italy).