BRIEF [O.A.] Ticehurst, J... N... G... Author: Ticehurst, J... N... G... Recipient: Haeckel, Ernst Dating: 17.10.1910
BRIEF [O.A.] Meissner, E... F... A... Author: Meissner, E... F... A... Recipient: Haeckel, Ernst Dating: 16.12.1910
BRIEF [O.A.] Pettit, A... Author: Pettit, A... Recipient: Haeckel, Ernst Corporation: Société de Biologie Dating: 20.02.1910
WIDMUNG Breitenbach, Wilhelm Author: Breitenbach, Wilhelm Recipient: Haeckel, Ernst Dating: 18.04.1910