BRIEF OHNE UMSCHLAG Waldeyer-Hartz, Wilhelm von Author: Waldeyer-Hartz, Wilhelm von Recipient: Haeckel, Ernst Dating: 12.10.1874
BRIEF OHNE UMSCHLAG Weidenreich, Franz Author: Weidenreich, Franz Recipient: Haeckel, Ernst Dating: 15.02.1909
BRIEF [O.A.] Ortmann, Arnold Ewald Author: Ortmann, Arnold Ewald Recipient: Haeckel, Ernst Dating: 17.06.1887
BRIEF [O.A.] Ortmann, Arnold Ewald Author: Ortmann, Arnold Ewald Recipient: Haeckel, Ernst Dating: 01.05.1888
POSTKARTE Ortmann, Arnold Ewald Author: Ortmann, Arnold Ewald Recipient: Haeckel, Ernst Dating: 03.07.1890