BRIEF [O.A.] Gümbel, C. Godfrey Author: Gümbel, C. Godfrey Recipient: Haeckel, Ernst Dating: 23.02.1904
BRIEF OHNE UMSCHLAG Voysey, Charles Frances Annesley Author: Voysey, Charles Frances Annesley Recipient: Haeckel, Ernst Dating: 07.10.1904
BRIEF OHNE UMSCHLAG Watts, Charles Albert Author: Watts, Charles Albert Recipient: Haeckel, Ernst Corporation: The Rationalist Press Association Dating: 03.10.1904
POSTKARTE Gibson, W. T. Author: Gibson, W. T. Recipient: Haeckel, Ernst Corporation: Marine Biological Station Dating: 10.05.1904
BRIEF OHNE UMSCHLAG McCabe, Joseph Author: McCabe, Joseph Recipient: Haeckel, Ernst Dating: 17.11.1904
POSTKARTE Mitchell, P. Chalmers Author: Mitchell, P. Chalmers Recipient: Haeckel, Ernst Corporation: Zoological Society Dating: 08.11.1904
BRIEF MIT UMSCHLAG Murray, John Author: Murray, John Recipient: Haeckel, Ernst Corporation: Challenger Lodge Dating: 24.12.1904
BRIEF OHNE UMSCHLAG Murray, John Author: Murray, John Recipient: Haeckel, Ernst Corporation: Challenger Lodge Dating: 03.06.1904