Autograph letter, Down, Beckenham, Kent, 28 October 1873, signed ("Charles Darwin"), to Alexander Kowalewski, thanking him for sending his memoir on the larva of the sea squirt ("I am much obliged for your Kindness in having sent me your memoir on the Larva of the Ascidians. . .) and closing "Yours faithfully & obliged / Charles Darwin." Charles DARWIN.