POSTKARTE Kiepert, Heinrich [?] Author: Kiepert, Heinrich [?] Recipient: Haeckel, Ernst Dating: 1887.12.?? [?]
BRIEF [O.A.] Tyrrell Leith, E... Author: Tyrrell Leith, E... Recipient: Haeckel, Ernst Dating: 15.10.1887
BRIEF [O.A.] Gadeau de Kerville, Henri Author: Gadeau de Kerville, Henri Recipient: Haeckel, Ernst Dating: 08.02.1887
BRIEF OHNE UMSCHLAG Laishley, Richard Author: Laishley, Richard Recipient: Haeckel, Ernst Dating: 15.06.1887
POSTKARTE Tyrrell Leith, E... Author: Tyrrell Leith, E... Recipient: Haeckel, Ernst Dating: 29.08.1887
BRIEF [O.A.] McIntosh, William C... Author: McIntosh, William C... Recipient: Haeckel, Ernst Dating: 12.09.1887