BRIEF [O.A.] Herold, P... R... Author: Herold, P... R... Recipient: Haeckel, Ernst Dating: 15.02.1876
BRIEF OHNE UMSCHLAG Spiller, Philipp Author: Spiller, Philipp Recipient: Haeckel, Ernst Dating: 19.01.1876
BRIEF OHNE UMSCHLAG Zimmermann, Otto Author: Zimmermann, Otto Recipient: Haeckel, Ernst Dating: 31.12.1876
BRIEF OHNE UMSCHLAG Petersen, Bertha; geb. Sethe Author: Petersen, Bertha; geb. Sethe Recipient: Haeckel, Ernst Dating: 14.05.1876
BRIEF OHNE UMSCHLAG Haeckel, Charlotte Author: Haeckel, Charlotte Recipient: Haeckel, Agnes Dating: 25.10.1876
