The investigation described in the present paper was commenced in 1895, with the aid of a grant of £100 from the Government Grant Committee of the Royal Society to meet the expenses of boat-hire, and a further grant of £25 has been made by the Society to assist in the production of the charts by which the paper is illustrated. The object of the investigation has been to gain an accurate knowledge of the distribution of the fauna on the sea-bottom over a continuous area, i n order to ascertain and where possible to explain the changes which take place in the animal population when the nature of the bottom-deposit changes. At the same time it was hoped that fresh light would be thrown upon the general question of the distribution of life on the sea-bottom and the principles upon which it depends.