BRIEFABSCHRIFT Ritter, Paul von Author: Ritter, Paul von Recipient: Haeckel, Ernst Dating: 07.01.1886
BRIEF OHNE UMSCHLAG Harnier, Eduard von Author: Harnier, Eduard von Recipient: Haeckel, Ernst Dating: 30.05.1886
BRIEF [O.A.] Patschkowski, M... Author: Patschkowski, M... Recipient: Haeckel, Ernst Dating: 07.07.1886
BRIEF [O.A.] Ludolphs, Fritz Author: Ludolphs, Fritz Recipient: Haeckel, Ernst Corporation: James Milne & Co. Dating: 22.05.1886
BRIEF [O.A.] Loewenthal, Wilhelm Author: Loewenthal, Wilhelm Recipient: Haeckel, Ernst Dating: 25.01.1886
BRIEF [O.A.] Lendenfeld, Robert von Author: Lendenfeld, Robert von Recipient: Haeckel, Ernst Dating: 18.04.1886