The type material of Peridinium gregarium Lombard et Capon, originally described from tidal pools in Southern California has been re-examined. Two of the three slides that have been deposited in the Herbarium, California State University, contained two

ABSTRACTA new dinoflagellate, Scrippsiella arenicola Horiguchi et Pienaar sp. nov., is described from tidal pools with sandy substrates along the east coast of South Africa. S. arenicola exhibits a vertical migratory rhythm which is in synchrony with

Validation here of the name Bysmatrum arenicola Horiguchi et Pienaar sp. nov. rather than Scrippsiella arenicola for this sand-dwelling dinoflagellate from South Africa also corrects the inadvertently invalid basionym publication.