p. 127 - 141 OBSERVATIONS SUR LA FAUNE SESSILE DES CHAMPS A CYSTOSEIRA BARBATA (AG.) DE LA MER NOIRE Victoria Tiganus Institute Roumain de Recherches Marines Constanta Abstract The qualitative and quantitative composition of the sessile fauna living on the algae Cystoseira barbata, than their seasonal variations during the period of the years 1970-1974 and the seasonal population structure dynamics of dominant species Mytilaster lineatus are presented in the paper. The type of spatial distribution of the principal species - Mytilaster lineatus, Mytilus galloprovincialis and Balanus improvisus - is also analysed.