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Darwin Correspondence Project

To Charles Lyell   7 December [1867]1

Down. | Bromley. | Kent. S.E.

Dec 7

My dear Lyell

I send by this post the Article in Vict. Institute2 With respect to frog’s spawn, if you remember in yr boyhood having ever tried to take a small portion out of the water you will remember that it is most difficult. I believe all the birds in the world might alight every day on the spawn of batrachians & never transport a single ovum.3 With respect to the young of molluscs, undoubtedly if the bird to which they were attached alighted on the sea, they wd be instantly killed; but a land bird wd I shd think never alight except under dire necessity from fatigue. This however has been observed near Heligoland, & land-birds after resting for a time on the tranquil sea, have been seen to rise & continue their flight. I cannot give you the reference about Heligoland without much searching.4

This alighting on the sea may aid you in your unexpected difficulty of the too easy diffusion of land-molluscs by the agency of birds.5

I much enjoyed my mornings talk with you6 & believe me | my dear Lyell | ever yours | Ch. Darwin

Footnotes

The year is established by the reference to the Journal of the Transactions of the Victoria Institute, which was first published in 1867, and by the information provided to Lyell for the second volume of the tenth edition of Principles of geology (C. Lyell 1867–8; see n. 3, below), which was published in 1868.
CD probably refers to Warington 1867 (see letter to George Warington, 7 October [1867] and n. 2, and letter to A. R. Wallace, 12 and 13 October [1867] and n. 20).
Lyell quoted CD’s observation that frog’s spawn does not adhere to the feet of birds in C. Lyell 1867–8, 2: 413. CD had confirmed an earlier observation that batrachians do not occur on oceanic islands in Origin, p. 393. See also Correspondence vol. 5, letter to J. D. Hooker, 10 June [1855].
Heligoland (now Helgoland) is an island off the coast of Denmark (Columbia gazetteer of the world). The migration of birds by way of Heligoland is discussed in Baird 1866, but without reference to land-birds resting on the sea; there is a copy of Baird 1866 in the Darwin Pamphlet Collection–CUL. Heinrich Gätke, who contributed information to Baird 1866, later wrote that he had observed three instances of small land-birds resting on the sea half a mile from Heligoland (Gätke 1895, p. 71).
Lyell considered the range of distribution of terrestrial molluscs, including the possibility of their transport by birds, especially waterfowl, in Principles of geology (see C. Lyell 1867–8, 2: 372–7, 399). However, there is no reference in C. Lyell 1867–8 to CD’s example from Heligoland.
CD evidently saw Lyell during his visit to London from 28 November until 7 December 1867 (CD’s ‘Journal’ (Correspondence vol. 15, Appendix II)).

Summary

Discusses transport of frog spawn and young molluscs by birds.

Letter details

Letter no.
DCP-LETT-5708
From
Charles Robert Darwin
To
Charles Lyell, 1st baronet
Sent from
Down
Source of text
American Philosophical Society (337)
Physical description
3pp

Please cite as

Darwin Correspondence Project, “Letter no. 5708,” accessed on 17 January 2019, http://www.darwinproject.ac.uk/DCP-LETT-5708

Also published in The Correspondence of Charles Darwin, vol. 15

letter