Many thanks for JDH's beautiful cirripede drawing. Questions on JDH's observations.
Down Farnborough Kent
My dear Hooker
Your drawing is quite beautiful; I cannot thank you enough, & I feel, as I before said guilty—your goodnature is as wonderful as mesmerism.— I have been reading heaps of papers on Cirripedia, & your drawing is clearer than almost any of them. The more I read, the more singular does our little fellow appear, & as you say, looking at its natural size, a microscope is a most wonderful instrument. How different would the drawing have been, if I had employed an artist! not to mention the invaluable assistance of having my loose observations confirmed, & the several points observed only by you.— I shall of course state this in the beginning of my paper, & when I have not seen the thing, give it on your authority.
I have a few questions to ask & I shd
(1) Is the fold at the posterior & lower end of stony, dentated valve, fimbriated & of the same texture, as the two inner fleshy & fimbriated valves? it is shaded in the same manner.—
(2) Regarding fig. 13 & 14, you speak as if you thought the kind of bars at the base of the two jaws were muscles; do you feel sure of this, for on the voyage & since they felt decidedly hard & shelly, & Burmeister has described similar hard supports to the jaws in Lepas.
(3) Did you happen to notice, whether the cherotherium footsteps pointed upwards or to the base of animal? I can look, if you do not remember.—
(4) I see you have not put in, any trace of the oblique articulation between the head & sternum; do you deliberately give it up? I certainly thought that there was one.—
(5) The head in fig. 10 seems to me hardly distinct enough dorsally from body; whereas in fig 11. it appears to me, just as I saw it; I can get artist to vary the line a trifle.
(6) Would you please return my own wretched drawing; & I shd be very much obliged for a copy, in same style as your others, of my fig. with legs retracted; the merest outline would do; I want it because the appearance of these larvæ are now so utterly different from what they were when alive & it shows position of legs when fully retracted.— I describe it, as pointed coffin-shaped, & twice as long as the egg in the last previous state, (your fig. 21) that is not including the two projections: I send a tracing of your two figures, for the scale sake: I see I state that the two anterior club-shaped organs in state on fig 21. are very much longer than in fig 20.
I have not knowledge enough to discuss the nature of the limbs in this larva; & indeed I doubt whether any one has, for its relations are to various very distinct families.
I return the lens, with very many thanks, & with ditto for having written to
Adie— My lens have been altered (for
Ever yours | My dear Hooker, C. Darwin
P.S. | I find that I have one other query.— In fig. 5. the inner & third tunic, is not represented as enveloping whole animal & ovisac, but folding in & terminating at the posterior & lower edge of ovisac; hence the ovisac appears like a reduplication of this 3d & inner membrane. My impression is different, viz that this 3d inner tunic is continuous with muscular tunic.— Pray mind, I beg you not for this or any other query, to dissect any more, indeed I doubt whether you have the specimens; for I will look to this point, only I have so very much more confidence in your observations than in mine own, that I am glad to know your impression.— I am drawing up my description, which runs out much longer than I expected or like.—
- f1 1012.f1Dated on the basis of CD's statement that he has had his lens altered. An entry in his Account Book (Down House MS) for 24 October reads: ‘Alteration of Microscope 3s. 6d.’
- f2 1012.f2Hooker had provided drawings of barnacles, including Cryptophialus minutus (see n. 3, below), which CD used in Living Cirripedia (1854), see p. 566 n. Hooker's drawings have not been found but some of CD's original figures, dating from the Beagle voyage, are in DAR 29.3: 72.
- f3 1012.f3Cryptophialus minutus, which CD originally called Arthrobalanus.
- f4 1012.f4No such paper has been found although CD evidently intended to publish one (see ‘Journal’; Correspondence vol. 3, Appendix II). The results of his researches were eventually published in Living Cirripedia (1854): 563–86.
- f5 1012.f5Burmeister 1834.
- f6 1012.f6Possibly an allusion to the small triangular points that cover the external membrane of Cryptophialus (see Living Cirripedia (1854), plate 23, figure 3), which resemble Cheirotherium footprints.
- f7 1012.f7Alexander James Adie, an optician and instrument-maker in Edinburgh.