BRIEF [O.A.] Marshall, William Author: Marshall, William Recipient: Haeckel, Ernst Dating: 07.03.1875
BRIEF [O.A.] Marshall, William Author: Marshall, William Recipient: Haeckel, Ernst Dating: 09.06.1875
BRIEF [O.A.] Stichling, Gottfried Theodor von Author: Stichling, Gottfried Theodor von Recipient: Haeckel, Ernst Dating: 24.12.1875