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Darwin Correspondence Project

From K. T. E. von Siebold   29 November 1871


29th of November | 1871.


Your kindness has forwarded me with two workes of such interest and importance (Monograph of the Cirripedia1 and Origin of species), that I was nearly ashamed to offer you the small contribution to the biology of lower animals, which now you will have already received, at least I ordered my librarian, Engelmann, some weeks ago, to send you in my name my last publication (Beiträge zur Parthenogenesis der Arthropoden).2 I hope my researches on parthenogenesis will show you, that this mode of propagation has ceased to be a mere curiosity, but has a peculiar signification and will best, I think, be considered as a case of atavisme.

The pseudova, this is sure, cannot be distinguished from the ova.3 Now nobody till now wondered about their development without interference of the male element. Ova, they said, are only capable of developement after having been fertilised.— In the successive generations of organic beings at first animals might have been found, that were propagated by pseudova, then, when the capacity of the animals to produce pseudova was no more sufficient for a sound development, a fertilisation was needed and afforded by the union of the two sexes in one being—the hermaprodit. Later these hermaphrodits were by and by separated into females and males, and these again by atavisme (inheritance from their first ancestors) became the faculty to produce ova (“pseudova”) which were developed without having been fertilised.

If in the beginning of my researches I had called pseudova all those eggs, which without having been fertilised are able of development, my adversaries—in England at least—would have been contented.

For your photograph, which I got through our common friend Lewes,4 my best thanks. I send mine in return5 and cannot conclude my letter without giving expression to my deep veneration and admiration for you, to whom we owe that actually the investigation of organic life has taken this new and for science so extraordinary useful direction.

I am, Sir, your most obedient | servant | Charles de Siebold


CD had published four volumes on Cirripedia (Living Cirripedia (1851) and (1854) and Fossil Cirripedia (1851) and (1854)).
CD’s copy of Siebold 1871 is in the Darwin Library–Down. The publisher was Wilhelm Engelmann.
For a contemporary view of Siebold’s contribution to the study of parthenogenesis, and for Thomas Henry Huxley’s coining of the term ‘pseudova’ for the ‘buds’ produced in the ovaries of organisms such as aphids but not capable of fertilisation, see Lankester 1872. John Lubbock had published several papers on the structural identity of ova and pseudova in the water-flea Daphnia (Lubbock 1857 and 1858a). CD cited Lubbock’s work in Variation 2: 360 (see also Correspondence vol. 16, letter from John Lubbock, 12 February [1868]). In Variation 2d ed., 2: 352–3, CD added a reference to Siebold 1871 as supporting Lubbock on this point.
George Henry Lewes.
The photograph has not been found in the Darwin Archive–CUL.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 26 vols to date. Cambridge: Cambridge University Press. 1985–.

Fossil Cirripedia (1851): A monograph on the fossil Lepadidæ, or, pedunculated cirripedes of Great Britain. By Charles Darwin. London: Palaeontographical Society. 1851.

Lankester, Edwin Ray. 1872. Siebold’s new researches in parthenogenesis. Nature, 10 October 1872, pp. 483–5, and 24 October 1872, pp. 523–5.

Living Cirripedia (1851): A monograph of the sub-class Cirripedia, with figures of all the species. The Lepadidæ; or, pedunculated cirripedes. By Charles Darwin. London: Ray Society. 1851.

Siebold, Karl Theodor Ernst von. 1871. Beiträge zur Parthenogenesis der Arthropoden. Leipzig: Wilhelm Engelmann.

Variation 2d ed.: The variation of animals and plants under domestication. By Charles Darwin. 2d edition. 2 vols. London: John Murray. 1875.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


Thanks CD for copies of the Origin and Cirripedia;

sends his latest publication in return [Beiträge zur Parthenogenesis der Arthropoden (1871)]. Discusses his work on parthenogenesis which, he believes, is a case of atavism.

Letter details

Letter no.
Carl Theodor Ernst von Siebold
Charles Robert Darwin
Sent from
Source of text
DAR 177: 159
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 8088,” accessed on 18 January 2020,

Also published in The Correspondence of Charles Darwin, vol. 19