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exist at all), b is very large, and c is small. Fig. 81.—One of the lozenge shaped spaces in the electric organ of malapterurus, magnified 200 diameters. s, space filled with fluid. To the left of a observe the electric tissue darkly tinted. Notice that it occurs on two sides of the lozenge-shaped space. See to the right of b the connective tissue wall of the space. n n, nuclei in electric tissue; n, nerve-fibre passing into electric tissue. The electric discs in this fish are epithelial and not muscular. The total number of discs, each of which is supplied with a nerve, is 2,000,000. All the nerves for the electric organs spring from two gigantic nerve-cells in the spinal cord, one for each lateral half. One nerve-process issues from each cell and, by dividing and subdividing, supplies each of the one million discs on one side of the body with a distinct nerve-fibre. The sum of the diameters of these nerve-fibres is very much greater than the diameter of the fibre that issues from the cell. It is evident, therefore, that the conducting matter of the nerve-fibres must increase in amount as we pass to the periphery of the body (p. 98). Thus, in my opinion, all these phenomena are