Form variations in the rotifer Brachionus calyciflorus Pallas from a perennial impoundment in India

All three classical forms of Brachionus calyciflorus Pallas viz., calyciflorus, dorcas and amphiceros were recognised in the impoundment. The form amphiceros was most abundant, and its occurrence is attributed to the presence of Asplanchna brightwelli in the tank. Euglena viridis appears to be the preferred food of B. calyciflorus in this impoundment.