GABRILOWITSCH, OSSIP (1878-1936), pianist and con ductor, was born in St. Petersburg (now Leningrad), on Feb. 7, 1878. He studied music at the Imperial Conservatoire in that city in the class of Tolstov and under the personal supervision of Anton Rubinstein, winning the Rubinstein prize in 1894. Later he continued his studies under Leschetizky in Vienna. At 18 he toured in Germany, Austria and England. In 1900 he toured the United States, and again in 1902, 1907-08. He married Mark Twain's daughter, Clara Clemens, the singer, in 1909. After hav ing conducted in Munich and Vienna he became conductor of the Detroit symphony orchestra in 1918.