BRIEF OHNE UMSCHLAG Bockelmann, Friedrich Author: Bockelmann, Friedrich Recipient: Haeckel, Ernst Dating: 07.05.1890
BRIEF [O.A.] Bettelheim, Anton Author: Bettelheim, Anton Recipient: Haeckel, Ernst Dating: 19.10.1890
BRIEF [O.A.] Van Bambeke, Charles Author: Van Bambeke, Charles Recipient: Haeckel, Ernst Dating: 22.01.1890
BILLET Bardeleben, Karl von Author: Bardeleben, Karl von Recipient: Haeckel, Ernst Corporation: Anatomische Gesellschaft Dating: 02.06.1890
BRIEF OHNE UMSCHLAG Palézieux-Falconnet, Aimé de Author: Palézieux-Falconnet, Aimé de Recipient: Haeckel, Ernst Dating: 15.07.1890