Thanks THH for corroborating his observations. Discusses metamorphosis of ovaria to cement organs. Ovaries, germinal vesicles, and anatomy of cirripedes. Difficulties of classification, and observation.
THH's article on Mollusca [Charles Knight, ed., English cyclopædia: a new dictionary of universal knowledge (1854–70) 3: 855–74].
Down Farnborough Kent
My dear Huxley.
I really am much obliged to you for looking at my preparations; I feel it quite a
comfort that some one sh
I felt to a degree you will hardly appreciate, the want of knowledge of minute or
microscopical structure: if I had to begin again, I
Lastly the main reason which caused me to separate the Cirripedes so completely as I have from ordinary Crustaceans, is, my firm belief, that the resemblance of the larvæ to Entomostraca is only analogical & that the natatory organs are not at all similar in the two,—that the law of development is very different. I give this conclusion briefly at p. 16 of the Balanidæ, & my reasons at tedious length at p. 102.—
How difficult a subject is the classification of the higher groups in any class: see how Dana & Milne Edwards, such competent judges, differ! Dana approves of my classification, but will not, from analogy alone, admit my views of the homologies of the limbs.—
Should you ever go on with subject, do read my account of Proteolepas: it strikes me as a truly extraordinary animal.—
I promise I will never bore you again on Cirripedes.—
I must just say, that you are quite right to doubt me in every way, for what blunders
are made. I stopped being sent to Royal Soc
Many thanks for your paper out of the Encyclop: on Mollusca,
of which I had heard from two quarters. I have read it with attention &
interest, for I had often wondered how a gasteropod, a bivalve, & cephalopod
An acephalous Mollusc has always looked to me a complete mystery, & I really
know no more about it, than a man does, who has only eat oyster patties; the relation of
the animal to the shell & crust being about the same in my eyes.—
There was no reason for your writing down to ignoramuses, & indeed without
beautiful figures, I sh
Pray believe me | Your's very sincerely | C. Darwin
- f1 1645.f1See letter to T. H. Huxley, 20 February . CD had asked Huxley to examine specimens of cirripedes in order to give his opinion on CD's interpretation of the structure of the cement glands and the female reproductive system.
- f2 1645.f2See Correspondence vol. 4, Appendix II.
- f3 1645.f3In Living Cirripedia (1851): 57–8, CD stated that he had traced in two genera of pedunculated cirripedes the ovarian ducts from the foot of the peduncle to the ‘two glandular masses’ thought by Georges Cuvier, owing to their position near the stomach, to be the salivary glands. Within these glands, CD discerned cellular masses resembling ‘ovigerms with their germinal vesicles and spots’. ‘Hence’, he wrote, ‘I conclude, that these two gut-formed masses are the true ovaria.’ (ibid., p. 58).
- f4 1645.f4For CD's use of embryological criteria for classification, see Correspondence vol. 4, Appendix II.
- f5 1645.f5CD discussed this difference of opinion in Living Cirripedia (1854): 17. Whereas James Dwight Dana, like CD, regarded the cirripedes as different enough from other Crustacea to form a distinct sub-class (Dana 1852–3, pt 2, p. 1407), Henri Milne-Edwards placed them as a sub-group of the higher Crustacea, the Entomostraca (Milne-Edwards 1852, p. 119).
- f6 1645.f6CD described the unusual homologies of the body of Proteolepas bivincta in Living Cirripedia (1854): 594–6. Owing largely to the differences in the development of this form from other cirripedes, CD classified Proteolepas as the sole species in its order.
- f7 1645.f7The paper has not been identified.
- f8 1645.f8T. H. Huxley 1855a, in which Huxley proposed an archetype for the Mollusca. See letter to T. H. Huxley, 20 February .