BRIEF [O.A.] Foerster, Fr... W... Author: Foerster, Fr... W... Recipient: Haeckel, Ernst Corporation: Ethische Kultur Dating: 13.04.1895
BRIEF [O.A.] Walther, Johannes Author: Walther, Johannes Recipient: Haeckel, Ernst Dating: 20.09.1895
BRIEF [O.A.] Walther, Johannes Author: Walther, Johannes Recipient: Haeckel, Ernst Dating: 28.12.1895
BRIEF [O.A.] Waagen, Wilhelm Author: Waagen, Wilhelm Recipient: Haeckel, Ernst Corporation: Paläontologisches Institut der K. K. Universität Dating: 03.12.1895
BRIEF [O.A.] Saporta, Louis C. J. Gaston de Author: Saporta, Louis C. J. Gaston de Recipient: Haeckel, Ernst Dating: 02.01.1895