BRIEF OHNE UMSCHLAG Hertwig, Oscar Author: Hertwig, Oscar Recipient: Haeckel, Ernst Dating: 08.12.1872
BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 02.01.1872
BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 24.01.1872
BRIEF [O.A.] Lortet, Louis Author: Lortet, Louis Recipient: Haeckel, Ernst Corporation: Museum d´Histore Naturelle Dating: 25.03.1872
BRIEF OHNE UMSCHLAG Lubbock, John Author: Lubbock, John Recipient: Haeckel, Ernst Corporation: Ray Society Dating: 09.03.1872