BRIEF [O.A.] Guldan, Georg Anton Author: Guldan, Georg Anton Recipient: Haeckel, Ernst Dating: 14.08.1876
BRIEF [O.A.] Brooks, K... Author: Brooks, K... Recipient: Haeckel, Ernst Corporation: Boston Society of Natural History Dating: 29.05.1876
BRIEF [O.A.] Packard, Alpheus S... Author: Packard, Alpheus S... Recipient: Haeckel, Ernst Corporation: Peabody Academy of Science Dating: 20.11.1876