BRIEF [O.A.] Schmelrik, Gregor Author: Schmelrik, Gregor Recipient: Haeckel, Ernst Dating: 10.09.1887
ANSICHTSKARTE Haeckel, Walther Author: Haeckel, Walther Recipient: Haeckel, Ernst; Haeckel, Agnes [Eltern] Dating: 16.10.1913
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Carl & Charlotte [Eltern] Dating: 27.03.1871
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Carl & Charlotte [Eltern] Dating: 21.03.1871
BRIEF [O.A.] Bucchich, Gregorio Author: Bucchich, Gregorio Recipient: Haeckel, Ernst Dating: 04.08.1894