BRIEF [O.A.] Schallwitz, Bruno Author: Schallwitz, Bruno Recipient: Haeckel, Ernst Dating: 27.09.1886
BRIEF [O.A.] Hundins, Paul Arthur Author: Hundins, Paul Arthur Recipient: Haeckel, Ernst Dating: 28.06.1886
ANSICHTSKARTE Haeckel, Walther Author: Haeckel, Walther Recipient: Haeckel, Ernst; Haeckel, Agnes Dating: 26.06.1886