BRIEF OHNE UMSCHLAG Ficalbi, Eugenio Author: Ficalbi, Eugenio Recipient: Haeckel, Ernst Corporation: Laboratorio di Zoologia e Anatomia Comparata della R. Università di Messina Dating: 14.04.1896
BRIEF OHNE UMSCHLAG Kükenthal, Willy Author: Kükenthal, Willy Recipient: Haeckel, Ernst Dating: 15.03.1896
BRIEF [O.A.] Lombardo, Franz Jama Author: Lombardo, Franz Jama Recipient: Haeckel, Ernst Dating: 01.06.1896