An account is presented of the restudy of seven forms of small dinoflagellate cysts from Upper Cretaceous flints of Belgium. The new genus Rhiptocorys is erected for forms having a hypotract much larger than the epitract, showing an unequal development of high crests and having an epitractal archaeopyle; the diagnosis for its type species, Rhiptocorys veligera (Deflandre), is emended. The new combination Druggidium fourmarierii (Lejeun-Carpentier) is proposed and a former variety elevated to specific status, as Druggidium leave (Lejeune-Carpentier). Emended diagnoses are proposed for both these taxa and for Dinogymnium avellana (Lejeune-Carpentier). Forms attributed by Lejeune-Carpentier (1951) to Phanerodinium cayeuxi Deflandre are reconsidered and one is redescribed as ? Phanerodinium sp. Photographs of all these forms are presented for the first time and interpretative drawings, many redrawn from the first author's original figures, supplement the text.