CD had been given the first four volumes of Alfred Edmund Brehm’s Illustrirtes Thierleben (Brehm et al. 1864–9). The plates listed were used in Descent. The species referred to are Cercopithecus diana (the Diana monkey; see Descent 2: 311), C. petaurista (the lesser white-nosed monkey; see Descent 2: 309), Pithecia satanas (the black saki, now Chiropotes satanas, the black-bearded saki; see Descent 2: 283), Chlamydera maculata (the spotted bowerbird; see Descent 2: 70), Paradisea rubra (the red bird-of-paradise, now Paradisaea rubra; see Descent 2: 75), Rupicola crocea (cock-of-the-rock, now Rupicola rupicola, the Guianan cock-of-the-rock; see Descent 2: 88), Cephalopterus ornatus (the umbrella bird, now the Amazonian umbrella bird; see Descent 2: 59), Lophornis ornatus (the tufted coquette; see Descent 2: 76), Steganurus underwoodi (now Ocreatus underwoodii, the booted racket-tail; see Descent 2: 77 (Spathura underwoodi)), Cupidonia americanus (the prairie chicken, now Tympanachus cupido, the greater prairie chicken; see Descent 2: 57), Polyplectron chinquis (now Polyplectron bicalcaratum, the grey peacock-pheasant; see Descent 2: 90), Philomachus pugnax (the ruff; see Descent 2: 42 (Machetes pugnax)), Palamedea cornuta (the anhima, now Anhima cornuta, the horned screamer; see Descent 2: 47: the plate was in Brehm et al. 1864–9, 4: 739, not 709 as given in the letter), and Rhynchaea capensis (the painted snipe, now Rostratula benghalensis, the greater painted snipe; see Descent 2: 202). See also letter to Bibliographisches Institut, Hildburghausen, 8 June 1868.

Cassell, Petter & Galpin had acquired translation rights to Brehm et al. 1864–9. The section on birds was published as Cassell’s book of birds (Brehm [1870–3]).