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Letter 1635

Darwin, C. R. to Huxley, T. H.

20 Feb [1855?]

    Summary Add

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    Sends specimens of sessile cirripedes for corroboration of their cementing apparatus.

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    Absence of anus in Brachiopoda and Alcippe cirripedes.



Down Farnborough Kent

Feb. 20th My dear Huxley

I send a few specimens of the cementing apparatus of Sessile Cirripedes, & shd be very glad if at some future time you wd have a look at them; merely that I may feel that I have one living witness of this odd structure which I have described. I send a single specimen, also, of an ovigerous frænum with its so-called glands; as this specimen was in act of moulting it entirely puts out of the question the bodies which you doubt about being foreign organisms.

I saw some time ago that you do not find any anus in the Brachiopod Molluscs; I may just mention that this is precisely the case with the Cirripede Alcippe in which rectum & anus are absolutely null.—

I have this morning just received your Article on Mollusca; I am particularly obliged to you for having sent it to me, as I had heard of it & shall be very glad to read it, as indeed everything which you write. But as far as criticism goes, I really do not know enough of the subject to pretend to offer an opinion worth the paper on which it shd be written.

Yours very truly | C. Darwin

This note & specimen &c all goes in a parcel for Dr Percy.—

Please look at specimens in following order, with good & varying light & moderately high powers. I shd like to have them back at some future time.— 280. Basal membrane of Coronula; showing cement-glands & ducts simplest structure in any Sessile Cirripede. 219. do of Chelonobia: ducts bifurcating more complicated; cement glands small. 203. do of Elminius: ducts very complicated: main cement trunk tortuous, like a great worm. 285. fragments of basis of Balanus tintinnabulum, after dissolution in acid, showing curious cement glands & bifurcating ducts 179. Piece of ovigerous frænum of Lepas anatiferum, showing glands. N.B. This specimen was in act of moulting, & the old membrane with the old glands & the new membrane with new glands, closely investing the corium, can both be plainly seen. Use 14th focal distance & good light.—

    Footnotes Add

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    f1 1635.f1
    Dated on the basis of the reference to T. H. Huxley 1855a (see n. 7, below).
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    f2 1635.f2
    See letters to T. H. Huxley, 8 September [1854] and 13 September [1854]. Huxley had examined specimens of cirripedes during his visit to Tenby the previous summer. CD had found the Balaninae, a sub-group of the Balanidae (sessile cirripedes) difficult to dissect, and he had therefore primarily based his views on the Lepadidae (pedunculated cirripedes) (see Living Cirripedia (1854): 134).
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    f3 1635.f3
    See Living Cirripedia, (1854): 134, where CD described the cementing apparatus in Lepadidae. It was his view that ‘the two cement-glands, with their contents, actually consist of ovarian tubes with their contents … in a modified condition.’
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    f4 1635.f4
    CD described the ovigerous fraena of the Lepadidae and the glandular bodies associated with them in Living Cirripedia (1851): 58–61.
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    f5 1635.f5
    T. H. Huxley 1854b.
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    f6 1635.f6
    Living Cirripedia (1854): 546.
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    f7 1635.f7
    T. H. Huxley 1855a. CD's copy is in the Darwin Pamphlet Collection–CUL.
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    f8 1635.f8
    John Percy, metallurgist, was a colleague of Huxley at the School of Mines.
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