ANSICHTSKARTE Hoyle, William Evans; Hoyle, Edith S. Author: Hoyle, William Evans; Hoyle, Edith S. Recipient: Haeckel, Ernst Dating: 31.12.1902
BRIEF OHNE UMSCHLAG Grazie, Marie Eugenie delle Author: Grazie, Marie Eugenie delle Recipient: Haeckel, Ernst Dating: 16.02.1895
BRIEF [O.A.] Aveling, Edward Bibbins Author: Aveling, Edward Bibbins Recipient: Haeckel, Ernst Corporation: Practical Science Laboratory Dating: 06.10.1882
BRIEF [O.A.] ...lemann, Theodor Author: ...lemann, Theodor Recipient: Haeckel, Ernst Dating: 10.04.1905
BRIEF [O.A.] Ziegler, Heinrich Ernst Author: Ziegler, Heinrich Ernst Recipient: Haeckel, Ernst Dating: 24.11.1900
BRIEF [O.A.] Theszóll, Charles Author: Theszóll, Charles Recipient: Haeckel, Ernst Dating: 23-02-1900