Cavolinia uncinata (Rang, 1829) uncinata (Rang, 1829) forma uncinata (Rang, 1829)
Colorless shell with flat dorsal side provided with five longitudinal ribs and two smaller ribs bordering posterior slits of aperture. Ventral side clearly vaulted, with transverse ribs, especially near aperture. Ventral side depressed medially near aperture; this depression is also found ventrally under the curved lip. No keel along lateral sides. Sculpture of faint growth lines and transverse striation near aperture. Ventral surface with faint hammered sculpture. Lateral spines almost straight. Caudal spine retained in adults, curved, relatively long. Dorsal lip curves strongly over aperture resembling a hood. Protoconch usually broken off, leaving open place of rupture. Shell length: 7.5 mm, width: 6.6 mm.