Odostomella Bucquoy, Dautzenberg & Dollfus, 1883: 167. Type species (by original designation) Rissoa doliolum Philippi, 1844; Recent, Sicily. Diagnosis. Small conical shells with strong axial ridges but no spiral sculpture. The protoconch is of type B tending to type A. Whorl flat-sided or slightly convex with coloured spiral bands. Head carries two blunt cephalic tentacles. At their base a propodium with bifid tip arises. Behind base of tentacles two small eyes. Foot broader than head, straight anteriorly and rounded posteriorly.
Remarks. Most authors (e.g. Nordsieck 1972, van der Linden & Eikenboom 1992) consider Odostomella a subgenus of Chrysallida Carpenter, 1857. The protoconch of Odostomella differs, however, much from those of the genus Chrysallida. The animals are also different (unpublished observations by the author and by S. Gofas on Odostomella doliolum (Philippi, 1844) from the Mediterranean Sea) from Chrysallida. In Chrysallida the cephalic tentacles are pointed and triangular, the propodium is entire, the foot slightly pointed posteriorly and bifid anteriorly. The head is broader than the foot. I therefore consider Odostomella as a genus separate from Chrysallida.