Genus Luidia Forbes, 1839

Type species. Luidia ciliaris (Philippi, 1837) (type by monotypy).

Remarks. The genus Luidia contains 49 species. Of the 12 Atlantic species, six occur in Brazil — L. alternata (Say, 1825), L. barbadensis Perrier, 1881, L. clathrata (Say, 1825), L. ludwigi Bell, 1917, L. sarsi Düben & Koren, 1845 and L. senegalensis (Lamarck, 1816) — L. patriae Bernasconi, 1941 occurs in Argentina and Uruguay, and five other species are restricted to the North Atlantic and Southeast Atlantic— L. atlantidea Madsen, 1950, L. ciliaris (Philippi, 1837), L. heterozona Fisher, 1940, L. lawrencei Hopkins & Knott, 2010, and L. sagamina Döderlein, 1920 .