Pallas, Peter Simon, born at Berlin in 1741; was invited in 1768 by Catherine II. of Prussia to fill the chair of natural science in the Academy of St. Petersburg. Next year he went with an expedition into Siberia to observe the transit of Venus, and until 1774 was engaged in a systematic investigation of the geography of the empire, extending his travels to the Chinese frontier. His death occurred at Berlin in 1811. His Spieilegia Zoologica is a work of some note.