Asks PHG to conduct an experiment to see if young littoral molluscs will cling to a duck's foot – CD seeks to explain distribution of molluscs without adopting E. Forbes's [continental extension] theory.
Moor Park | Farnham | Surrey
My dear Sir
I have thought that perhaps in course of summer you would have an opportunity &
would be so very kind as to try a little experiment for me.— I think I can tell best what I want, by telling what I have done.
The wide distribution of same species of F. Water Molluscs has long been a
great perplexity to me: I have just lately hatched a lot & it occurred to me
that when first born they might perhaps have not acquired phytophagous habits, &
might perhaps like nibbling at a Ducks-foot.— Whether this is so I do not
know, & indeed do not believe it is so, but I found when there were many
very young Molluscs in a small vessel with aquatic plants, amongst
which I placed a dried Ducks foot, that the little barely visible shells often
crawled over it, & that they adhered so firmly that they
Now you will remember that E. Forbes argues chiefly from the difficulty of imagining how littoral sea-molluscs could cross tracts of open ocean, that islands, such as Madeira must have been joined by continuous land to Europe: which seems to me, for many reasons, very rash reasoning.— Now what I want to beg of you, is, that you would try an analogous experiment with some sea-molluscs, especially any strictly littoral species,—hatching them in numbers in a smallish vessel & seeing whether, either in larval or young shell state they can adhere to a birds foot & survive say 10 hours in damp atmosphere out of water. It may seem a trifling experiment, but seeing what enormous conclusions poor Forbes drew from his belief that he knew all means of distribution of sea-animals, it seems to me worth trying.—
My health has lately been very indifferent, & I have come here for a fortnight's water-cure.—
I owe to using your name a most kind & most valuable correspondent, in
I hope you will forgive my troubling you on the above point & believe me, | My dear Sir | Your's very sincerely | Ch. Darwin
P.S. | Can you tell me, you who have so watched all sea-creatures, whether male Crustaceans ever fight for the females: is the female sex in the sea, like on the land, “teterrima belli causa”?
I beg you not to answer this letter, without you can & will be so kind as to tell about Crustacean Battles, if such there be.—
- f1 2082.f1The year is given by CD's visit to Moor Park (see n. 6, below) and by the reference to the correspondence between CD and Richard Hill (see n. 7, below).
- f2 2082.f2Gosse and his family usually spent the winter in London and the summer at the seaside, where he pursued his researches on marine organisms.
- f3 2082.f3This experiment is recorded in CD's Experimental book, pp. 21–2 (DAR 157a). CD included this case in the discussion of the geographical distribution of freshwater organisms in Origin, p. 385.
- f4 2082.f4Edward Forbes discussed at length the geographical distribution of Mollusca, and particularly those inhabiting shallow tidal zones (E. Forbes 1846, pp. 352–90), and concluded that ‘there must have been either a connexion or such a proximity of land as would account for the transmission of a non-migratory terrestrial, and a littoral marine fauna.’ (p. 383).
- f5 2082.f5According to Edmond Gosse, his father sent CD ‘ample notes’ on this subject (E. Gosse 1890, p. 269).
- f6 2082.f6CD was at Moor Park, Surrey, from 22 April to 6 May 1857 (‘Journal’; Appendix II).
- f7 2082.f7See letters from Richard Hill, 10 January 1857 and 12 March 1857.
- f8 2082.f8A reference to Horace, Satires, 1. 3. 107, in which women were deemed ‘the most foul cause of war’. CD had asked T. V. Wollaston the same question (see letter from T. V. Wollaston, [12 April 1857]).