BRIEF [O.A.] Wagenschieber, W... Author: Wagenschieber, W... Recipient: Haeckel, Ernst Dating: 12.09.1863
BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 24.06.1863
BRIEF OHNE UMSCHLAG Hein, Reinhold Author: Hein, Reinhold Recipient: Haeckel, Ernst Dating: 06.04.1863
BRIEF OHNE UMSCHLAG Marshall, William Author: Marshall, William Recipient: Haeckel, Ernst Dating: 27.03.1863
BRIEF OHNE UMSCHLAG Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Dating: 22.11.1863