In order to verify the aragonite temperature scale which was established by Horibe and Oba (1972) the ₁₈O contents in the shell of a living shallow water mollusc (Anadara broughtnii) were measured. The temperatures calculated with the Horibe-Oba aragonite scale were in good agreement with the seasonal variations observed in the surrounding water temperature. The temperature calculated by the same equation using the₁₈O content in the shell of a deep water mollusc, where the ₁₈O content of sea water is known, was quite consistent with the measured temperature of the sea water at the depth from which the shell was obtained. -- AATA