The investigation of the food of larval and post-larval fish from Plymouth Sound and beyond for three years has brought out some interesting facts. For the first two years fresh material from the tow-nets was examined together with old material from the Young Fish Trawl (Lebour, 1918, 1919). During the present year, in addition to the tow-nettings, fresh material from the Young Fish Trawl was also available from July to the end of September, and several fish from outside the Sound examined which had not been obtainable for the last two years. We thus have a fair number of young Mackerel, Ling, Hake and Gurnard and several others.