In both starfish and sea-urchin eggs the K is higher than the Na, although in sea water the relation is reversed. The Ca:Mg ratio in the latter is about 1:2 and in the former the Mg in the ratio is slightly lower than 2. Total P is higher in the starfish than in the urchin egg, but the distribution between lipoid and acid-soluble is about the same. Sulphate in the urchin egg is very low and Fe relatively abundant. The cation equivalence is much higher than the anioninboth eggs.