Comments on JL's paper on Daphnia, ["An account of methods of reproduction in Daphnia and of the structure of the ephippium", Philos. Trans. R. Soc. Lond. 147 (1857): 79–100].
My dear Lubbock.
I received this morning your paper & have read it attentively. It is to me decidedly interesting, & as a whole
very clear. But without some special object (& trusting not much to my own
judgment) I sh
In p. 1. I sh
p. 1. you use word “former”; in my opinion every author
who uses “former & latter” ought to be executed; &
p. 10 is not very clear in parts, owing, I think, to your varying your terms “cells” “eggs” “darkened” “brown”
p. 18. Surely ought you not to give your own facts pretty full (& references to others) about ova being produced by females for successive times without males.— When I met this page, I turned back, thinking that I had overlooked some whole page.—
I have appended a few pencil marks to some sentences, which required twice reading over, which no sentence ought to do.
Do not mistake my first remarks, & suppose for one moment that I do not think
your present materials worth publishing: only I
Farewell— I am sorry that you are poorly— I hope & fully expect that I shall be well enough to see you on Wednesday if you come
Adios | C. Darwin
The evidence in regard to fecundation & the 2 sorts of eggs is thus, is it not?—
Ordinary eggs are produced for 2 or 3 successive times in same individual without males; but not I suppose for successive generations.— I suppose existence of a spermatheca is very improbable.—
Ephippial eggs are never produced without presence of males, (& you have a good
long experience in this?) but the presence of males does not
necessarily in your experience, induce ephippial eggs.— ie Whilst males are
present & even seen attached to females, “ordinary” eggs are
produced.— Is this not so? Certainly evidence seems pretty strong for your
view: but yet, if I have put the case right, still further evidence or still longer
- f1 1979.f1Dated by the reference to the manuscript of Lubbock 1857.
- f2 1979.f2Lubbock sent CD the manuscript of his paper on reproduction in Daphnia (Lubbock 1857). CD communicated the paper to the Royal Society on 22 December 1856 (see Proceedings of the Royal Society of London 8 (1856–7): 352–4). It was published in full in the Philosophical Transactions of the society.
- f3 1979.f3In the closing pages of the published version (Lubbock 1857, pp. 95–9), Lubbock summarised recent work on parthenogenesis in the Articulata, including Crustacea and insects. He drew a parallel between ‘agamic’ reproduction in Daphnia and in plants that apparently produced agamic seeds, and suggested that there was no fundamental difference between the two kinds of eggs produced by Daphnia: the eggs formed ‘parts of one and the same series’ (p. 99).
- f4 1979.f4Lubbock distinguished the common, parthenogenic mode of reproduction in Daphnia from the less frequent and less understood mode of sexual reproduction. Although he stated that had not been able to prove that the ephippial eggs (so named because they were found in a specialised compartment of the animal's carapace known as the ephippium) were the result of sexual reproduction, he presented his reasons for believing that this was the case. He also claimed to have identified the male sexual organs and the animal's spermatozoa, hitherto unobserved.
- f5 1979.f5In the final version of the paper, Lubbock did not use the expression ‘at once evident’ (Lubbock 1857, p. 79).
- f6 1979.f6Thomas Babington Macaulay.
- f7 1979.f7CD refers to the section in Lubbock's paper in which Lubbock described the appearance and subsequent development of agamic eggs after their deposition (Lubbock 1857, p. 83).
- f8 1979.f8Lubbock cited William Baird (Baird 1850) and Henri Milne-Edwards (Milne-Edwards 1834–40) in Lubbock 1857, pp. 84–5, before stating that Hercule Eugène Gregoire Straus-Durckheim's description of the anatomy of the
- f9 1979.f9In the published paper, Lubbock stated his belief that there was no spermatheca in which the female could retain live sperm to fertilise successive broods (Lubbock 1857, p. 88).
- f10 1979.f10Lubbock stated: ‘I have not succeeded in … obtaining ephippial eggs from isolated specimens’ (Lubbock 1857, p. 87). However, he went on to describe experiments in which isolated females developed ephippia and concluded that ‘these experiments prove that ephippia can be produced without male influence. I only, however met with seven instances, though I have had at least 400 broods of agamic eggs produced by females kept separate from males’ (p. 88).