BILDPOSTKARTE Ihering, Hermann von Author: Ihering, Hermann von Recipient: Haeckel, Ernst Dating: 18.12.1910
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 Krauseneck, Gustav Adolf Author: Krauseneck, Gustav Adolf Recipient: Haeckel, Ernst Dating: 03.09.1910
BILDPOSTKARTE Sarasin, Paul; Sarasin, Fritz Author: Sarasin, Paul; Sarasin, Fritz Recipient: Haeckel, Ernst Dating: 12.06.1910