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Darwin Correspondence Project

To Henry Denny   12 August [1844]

Down Bromley Kent

Aug 12

Dear SIr

I took such especial pains, in myself always doing up every specimen, that I am astonished & can hardly believe there has been a mistake.— I have turned to my catalogoue, made on the spot, & I there enter a memorandum to have these Pediculi, compared with those of the Domestic Guinea Pig.—1 It occurs to me that I may have transposed my numbers in copying them for you.— so I will recopy them. 658.from the Ctenomys Braziliensis (a burrowing rodent) or ⁠⟨⁠    ⁠⟩⁠2 646from the Aperea ie. the Cavaia Cobaya 638—from the Synallaxis3 1185.from Man4 It is possible I may have brought home the dead specimen in the same bag with birds, & the parasites from the latter have crawled on the former; but I feel no doubt that I with my own hands took the Lice off the Aperea & put them into spirits

Ever yours, &c | C. Darwi⁠⟨⁠n⁠⟩⁠


The Beagle ‘Catalogue for animals in spirits of wine’ at Down House lists the specimens. No. 646 is ‘Pediculi from the Aperea’. On the corresponding page of notes is CD’s note: ‘As this animal is supposed to be the wild Guinea-pig, it would be interesting to compare these parasites, with those inhabiting, an Europæan individual, to observe whether they have been altered by transportation & domestication: It would be curious to make analogous observation with respect to various tribes of men.—’
The Beagle catalogue (Down House MS) reads ‘Pediculi from Toco Toco’ (the burrowing rodent).
In both the Beagle catalogue and on a single sheet list of ‘Insects in spirits of wine’ (DAR 29.3: 44) number 638 is listed as from ‘head of Certhia’. The Beagle catalogue (Down House MS) entry reads ‘Pediculi, very minute, but curious from head of Certhia (1248)’. Synallaxis major was a later identification by John Gould, which was then corrected to ‘Anumbius acuticaudatus, G. R. Gray’ in Birds, Corrigenda. CD’s field descriptions in Birds (pp. 76–7) of Synallaxis correspond to those of Certhia made during the voyage (see Ornithological notes, p. 220).
The Beagle catalogue refers to p. 315 of CD’s Zoological Diary (DAR 31.2), which contains the account of the Sandwich Islanders’ lice (see letter to Henry Denny, 3 June [1844], n. 1).


Birds: Pt 3 of The zoology of the voyage of H.M.S. Beagle. By John Gould. Edited and superintended by Charles Darwin. London: Smith, Elder and Co. 1839–41.


Can hardly believe he made a mistake in specimens sent to HD. Recopies numbers in case he transposed them. [Has to do with lice taken from a specimen of aperea and put into spirits during Beagle voyage.]

Letter details

Letter no.
Charles Robert Darwin
Henry Denny
Sent from
Source of text
American Philosophical Society (Mss.B.D25.)
Physical description
ALS 2pp

Please cite as

Darwin Correspondence Project, “Letter no. 770,” accessed on 13 September 2023,

Also published in The Correspondence of Charles Darwin, vol. 3