IN recent years importance has been laid on the study of sedentary organisms of enclosed waters as these cause considerable damage to the submerged piles, pillars and buoys and impede navigation due to their accumulation on ships' bottom. Interest in the study of these organisms was first initiated by Visscher (1927) and was followed by several workers (Coe, 1932 ; Johnson and Miller, 1935 ; Coe and Allen, 1937 ; Zobell, 1938 ; Edmondson and Ingram, 1939 ; Pomerat and Reiner, 1942 ; McDougall, 1943 ; Edmondson, 1944 ; Richard and Clapp, 1944 ; Graham and Helen, 1945 ; Fuller, 1946 ; Pomerat and Weiss, 1946 ; Weiss, 1948 ; Pyefinch, 1948) whose observations reveal that the more important of the physicochemical factors influencing the composition and abundance of the sedentary communities are temperature, salinity, light, current, pollution, phosphate-nitrite contents, nature of substratum and depth. Among the recent investigations may be listed the studies of Allen and Wood (1950), Smith, Williams and Davis (1950), the contribution of Woods Hole Oceanographic Institution (1952), Ralph and Hurley (1952) and Knight-Jones and Clifford Jones (1955). 

sedentary organisms, distribution, environmental factors, succession, Madras harbour