To Melchior Neumayr   9 March 1877

Down, | Beckenham, Kent.

Mar 9. 1877

Dear Sir

From having been obliged to read other books, I finished only yesterday your essay on “Die Congerien &c”.1

I hope that you will allow me to express my gratitude for the pleasure & instruction which I have derived from reading it. It seems to me to be an admirable work; & is by far the best case which I have ever met with, shewing the direct influence of the conditions of life on the organization.

Mr Hyatt, who has been studying the Hilgendorf case, writes to me with respect to the conclusions at which he has arrived, & these are nearly the same as yours.2 He insists that closely similar forms may be derived from distinct lines of descent; & this is what I formerly called analogical variation.3 There can now be no doubt that species may become greatly modified through the direct action of the environment; I have some excuse for not having formerly insisted more strongly on this head in my Origin of Species, as most of the best facts have been observed since its publication.4

With my renewed thanks for your most interesting essay; & with the highest respect, I remain | dear Sir | yours very faithfully | Charles Darwin

LS(A)

1
An annotated copy of Neumayr and Carl Paul’s Die Congerien- und Paludinenschichten Slavoniens und deren Faunen: ein Beitrag zur Descendenz-Theorie (The Congeria and Paludina strata of Slavonia and their faunas: a contribution to the theory of descent; Neumayr and Paul 1875) is in the Darwin Library–CUL. Paul wrote the geological part and Neumayr the palaeontological; Congeria is a genus of bivalve molluscs and Paludina (a synonym of Vivipara) a genus of gastropod molluscs. The book traces the lineage of gastropod shell evolution in freshwater Pliocene sands and clays of Slavonia (Croatia); for a recent analysis, see Posilović and Bajraktarević 2010.
2
See letter from Alpheus Hyatt, January 1877 and n. 9. Hyatt had questioned Franz Hilgendorf’s phylogeny of the Steinheim fossil shells, which suggested that all forms were directly descended from a single foundation species.
3
In Origin, pp. 427–8, CD distinguished ‘real affinities’ (those which revealed common descent) from analogical or adaptive resemblances: animals, belonging to two most distinct lines of descent, may readily become adapted to similar conditions, and thus assume a close external resemblance; but such resemblances will not reveal—will rather tend to conceal their blood-relationship to their proper lines of descent. We can also understand the apparent paradox, that the very same characters are analogical when one class or order is compared with another, but give true affinities when the members of the same class or order are compared one with another.
4
CD was sceptical about ‘direct action of the environment’ contributing to evolutionary change, but he recognised it as a more potent force in the development of the individual organism. In the first edition of Origin, p. 206, he wrote: For natural selection acts by either now adapting the varying parts of each being to its organic and inorganic conditions of life; or by having adapted them during long-past periods of time: the adaptations being aided in some cases by use and disuse, being slightly affected by the direct action of the external conditions of life, and being in all cases subjected to the several laws of growth. In Origin 5th ed., pp. 253–4, he removed ‘slightly’, and in Origin (1876), pp. 166–7, he changed ‘some’ to ‘many’.

Manuscript Alterations and Comments

0.1 Down, | Beckenham, Kent.] before del ‘Railway Station | Orpington. S.E.R.’
3.2 &] after del ‘&’
3.6 formerly] interl in CD’s hand

Please cite as “DCP-LETT-10884,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-10884