BILDPOSTKARTE Eggeling, Heinrich von Author: Eggeling, Heinrich von Recipient: Haeckel, Ernst Dating: 03.09.1910
BILDPOSTKARTE Fraas, Eberhard Author: Fraas, Eberhard Recipient: Haeckel, Ernst Corporation: Königl. Naturalien-Cabinet in Stuttgart Dating: 09.08.1910
BILDPOSTKARTE Ihering, Hermann von Author: Ihering, Hermann von Recipient: Haeckel, Ernst Dating: 18.12.1910
BILDPOSTKARTE Umlauff, Heinrich Author: Umlauff, Heinrich Recipient: Haeckel, Ernst Corporation: J. F. G. Umlauff Naturalien-Handlung und Museum Dating: 01.01.1910
BILDPOSTKARTE Krauseneck, Gustav Adolf Author: Krauseneck, Gustav Adolf Recipient: Haeckel, Ernst Dating: 03.09.1910
BILDPOSTKARTE Ernst Haeckel Author: Ernst Haeckel Recipient: Sprenger, Gustav; Sprenger, Therese Dating: 31.12.1910