BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Focke, Wilhelm Olbers Dating: 27.10.1857
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Lachmann, Johannes Dating: 15.02.1857
BRIEF OHNE UMSCHLAG Schenk, August Author: Schenk, August Recipient: Haeckel, Ernst Dating: 21.02.1857
BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 26.07.1857
BRIEF OHNE UMSCHLAG Lachmann, Johannes Author: Lachmann, Johannes Recipient: Haeckel, Ernst Dating: 15.11.1857
BRIEF OHNE UMSCHLAG Kölliker, Albert Author: Kölliker, Albert Recipient: Haeckel, Ernst Dating: 05.01.1857
BRIEF OHNE UMSCHLAG Krüger, Gustav Adolph Author: Krüger, Gustav Adolph Recipient: Haeckel, Ernst Dating: ca. 1857/1858