Using X-ray microanalysis, the contents and distribution of Na, K, Mg, Ca and some other elements were studied in ovary and ovariole oocytes of the grass frog R. temporaria. The increased K and Mg concentrations were found in the oocyte cytoplasm pigmented zone. The concentration of K in the nucleus is higher than in the cytoplasm, whereas that of P and S lower. The same concentration of Na was found in the nucleus and cytoplasm. High concentrations of K and S are noticed in the oocyte jelly envelope.
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