# To T. H. Huxley  20 February [1855]1

Down Farnborough Kent

Feb. 20th

My dear Huxley

I send a few specimens of the cementing apparatus of Sessile Cirripedes,2 & 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.3 I send a single specimen, also, of an ovigerous frænum with its so-called glands;4 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;5 I may just mention that this is precisely the case with the Cirripede Alcippe in which rectum & anus are absolutely null.—6

I have this morning just received your Article on Mollusca;7 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.—8

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 $\frac{1}{4}$th. focal distance & good light.—

## Footnotes

Dated on the basis of the reference to T. H. Huxley 1855a (see n. 7, below).
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).
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.’
CD described the ovigerous fraena of the Lepadidae and the glandular bodies associated with them in Living Cirripedia (1851): 58–61.
T. H. Huxley 1854b.
Living Cirripedia (1854): 546.
T. H. Huxley 1855a. CD’s copy is in the Darwin Pamphlet Collection–CUL.
John Percy, metallurgist, was a colleague of Huxley at the School of Mines.

## Summary

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

Absence of anus in Brachiopoda and Alcippe cirripedes.

## Letter details

Letter no.
DCP-LETT-1635
From
Darwin, C. R.
To
Huxley, T. H.
Sent from
Down
Source of text
Imperial College of Science, Technology and Medicine Archives (Huxley 5: 23, 372, 376)
Physical description
4pp, encl Amem 2pp