During the rise of National Socialism, he was dismissed from his position 1933 and emigrated via Switzerland to St. Petersburg, were he received a position at the Severtsov Evolution and Morphology Institute of the Soviet Academy of Sciences.
During the rise of National Socialism, he was dismissed from his position and in 1933 emigrated to Switzerland. Soon afterwards he moved to Moscow, where he worked at the Severtsov Evolution and Morphology Institute of the Soviet Academy of Sciences.