BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Senckenbergische Naturforschende Gesellschaft Dating: 07.04.1909
BRIEF [O.A.] Jassoy, A... Author: Jassoy, A... Recipient: Haeckel, Ernst Corporation: Senckenbergische Naturforschende Gesellschaft Dating: 25.10.1903
BRIEF [O.A.] Wendt, A... H... Author: Wendt, A... H... Recipient: Haeckel, Ernst Corporation: Senckenbergische Naturforschende Gesellschaft Dating: 05.04.1914
BRIEF [O.A.] Blum, J... Author: Blum, J... Recipient: Haeckel, Ernst Corporation: Senckenbergische Naturforschende Gesellschaft Dating: 25.12.1897
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Senckenbergische Naturforschende Gesellschaft Dating: 01.06.1897
BRIEF [O.A.] Reichenbach, Heinrich Author: Reichenbach, Heinrich Recipient: Haeckel, Ernst Corporation: Senckenbergische Naturforschende Gesellschaft Dating: 03.07.1886