BRIEF [O.A.] Sohncke, Leonhard Author: Sohncke, Leonhard Recipient: Haeckel, Ernst Dating: 11.01.1896
BRIEF [O.A.] Zittel, Karl Alfred von Author: Zittel, Karl Alfred von Recipient: Haeckel, Ernst Dating: 18.11.1896
BRIEF [O.A.] Schultze, Leonhard Author: Schultze, Leonhard Recipient: Haeckel, Ernst Dating: 23.12.1896
BRIEF [O.A.] Herdman, William Abott Author: Herdman, William Abott Recipient: Haeckel, Ernst Corporation: British Association for the Advancement of Science Dating: 25.02.1896
BRIEF [O.A.] Schleicher, Fréres Author: Schleicher, Fréres Recipient: Haeckel, Ernst Dating: 02.09.1896