New Australian Late Mesozoic species of Gymnodinium and Deflandrea (Dinoflagellata) and Odontochitina and Palaeotetradinium (Incertae Sedis) have been described. A new species of Wetzeliella from a South Australian Eocene deposit has thrown light on the taxonomic position of the genus. Hystrichokolporna cinctum Klumpp (Hystrichosphaeridae) has been recorded from Victorian Tertiary deposits.