Five polymorphic forms, including a new one, of the brachionid rotifer—Brachionus quadridentatus, are described from the Morar channel in Gwalior. These are the nominate formquadridentatus, formcluniorbicularis, formrhenanus, formbrevispina and formmonospina nov. The variation in different morphological forms is due to the emergence, development and elongation of postero-lateral and postero-median spines, and changes in the size of lorica. The present communication forms the first report of polymorphosis inB. quadridentatus from India.