p. 141 - 150 SOME DATA CONCERNING THE BIOMETRY AND ECOLOGY OF THE BIVALVE MYTILASTER LINEATUS (GMELIN) Marian-Traian Gomoiu and Victoria Tiganus Romanian Marine Research Institute Constanta Abstract On the basis of biometrical measurements of 11,000 individuals out of 10 samples collected at different depths, the quantitative parameters that characterize Mytilaster lineatus specimens from the Romanian Black Sea shore and their tendency of growth were established. Mytilaster lineatus has a large morphological variability due to the permanent and nonperiodical fluctuations of the ecological factors.