Introduction. "Tenth of a series of papers dealing with the plankton content of a series of nets drawn through a cylinder of water off the coast of Bermuda on the Bermuda Oceanographic Expeditions of the Department of Tropical Research under the direction of Dr. William Beebe. Full details as to this circle of water, and of the dates, depths, etc., of the nets will be found in Zoologica, Vol. XIII, Nos. 1, 2 and 3, pp. 1-45, and Zoologica, Vol. XXI, No. 3, pp. 69-73."