p. 83-94 NOTES ON PLATYMONAS IMPELLUCIDA (McLachlan & Parke) SPECIES IN MONO-ALGAL CULTURES Pia Elena Mihnea Romanian Marine Research Institute - Constanta Abstract A new species found in the Black Sea, Platymonas impellucida McLachlan & Parke, is described. Were analysed the rithms of its growth in cul- ture conditions. Nine variants of the same medium were; the environ- mental conditions were maintained constant and identical for each alternative. It was attempted a comparison of natural populations with the experimental ones, and the data regarding differences found were discussed.