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Darwin Correspondence Project

From William Houghton   18 October 1867

Preston Rectory | Wellington Salop

Oct. 18. ’67.

Dear Mr. Darwin.

If you can spare 5 minutes, will you kindly inform me whether, if you can remember, your researches on the planarian worms satisfied yourself as to the existence, or absence, of a nervous system in these little beasts?1 Some German Naturalists ascribe to them a Nervous system.2 I have lately occupied myself with studying these annelids3—i e.—the common fresh water kinds—& can trace no appearance of the most rudimentary nervous system—spite of my utmost endeavours to find some gangliæ.4

It is hardly fair to trouble one whose hands are so full of work, & I apologise for this note.

I suppose we shall shortly have your new book.5 I think it a subject of congratulate that, in these days, any theories if well supported are likely to meet with fair discussion. At any rate we are making progress, despite the women & the parsons!

I hope to be in London next January, & to have the pleasure of once more seeing you at that time.6

Eyton goes on as usual. Have you seen his book on the osteology of Birds?7 Owen thinks Huxley has lately cribbed an idea from him.8

I sincerely trust your health improves, & with kindest regards I am | Yours most sincerely | W. Houghton

Charles Darwin Esq | &c &c

PS. | Some months ago I heard, indirectly from a medical man, of a supposed case of fertility in hybrids between the domestic fowl & pheasant—& took a long walk of 12 miles to see into the matter— All I found was that the hens may have occasionally been trod by the cock-pheasants, & that the supposed offspring were simply the result of a connection between the game fowl & the pheasant variety of the domestic cock. (Golden Spangled Hawks’—)


While on the Beagle voyage, CD had found several new species of planarians; he later wrote a paper describing twelve terrestrial and five marine species, but did not describe a nervous system (‘Planariae’; see also Journal of researches, pp. 30–1, Correspondence vol. 1, and R. D. Keynes 2002, pp. 82–4).
See, for example, Schultze 1851, pp. 21–3.
Houghton mistakenly refers to planarian worms as ‘annelids’. Planarian worms belong to the class Turbellaria (free-living acoelomate flatworms). The Annelida were the class (now phylum) of segmented coelomate worms.
In Journal of researches, p. 31, CD had commented on the difficulty of preserving planarians for observation, noting, ‘immediately the cessation of life allows the ordinary laws of change to act, their entire bodies become soft and fluid, with a rapidity which I have never seen equalled’. In an article on land planarians (Schultze 1856, p. 33), Max Johann Sigismund Schultze discussed the special preparation of specimens for detailed studies of their internal organs.
Houghton refers to Variation, which was published in January 1868.
According to his journal, CD visited London in late November 1867 and in March 1868 (see ‘Journal’ (Correspondence vol. 15, Appendix II) and Correspondence vol. 16, Appendix II).
The main part of Thomas Campbell Eyton’s Osteologia avium (Eyton 1867–75) was published in 1867. A supplement was published in 1869 and a second supplement in three parts appeared between 1873 and 1875.
The references are to Richard Owen and Thomas Henry Huxley. Houghton may be referring to Huxley’s work on the classification of the bird species Opisthocomus cristatus (the hoatzin). In a paper on bird classification read in April 1867, Huxley had briefly discussed the species but admitted that he had had only an incomplete skull to study (T. H. Huxley 1867, p. 435). Eyton later provided Huxley with a complete skeleton of the bird, and Huxley published his conclusions on its classification in a later paper (T. H. Huxley 1868, pp. 304–11; see also Correspondence vol. 16, letter from T. C. Eyton, 23 August [1868]).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Eyton, Thomas Campbell. 1867–75. Osteologia avium; or, a sketch of the osteology of birds. 1 vol. and 2 supplements. Wellington, Salop.: R. Hobson.

Huxley, Thomas Henry. 1867. On the classification of birds; and on the taxonomic value of the modifications of certain of the cranial bones observable in that class. [Read 11 April 1867.] Proceedings of the Zoological Society of London (1867): 415–72.

Journal of researches: Journal of researches into the geology and natural history of the various countries visited by HMS Beagle, under the command of Captain FitzRoy, RN, from 1832 to 1836. By Charles Darwin. London: Henry Colburn. 1839.

Keynes, Richard Darwin. 2002. Fossils, finches and Fuegians: Charles Darwin’s adventures and discoveries on the Beagle, 1832–1836. London: HarperCollins Publishers.

Schultze, Max Johann Sigismund. 1856. Beiträge zur Kenntnis der Landplanarien nach Mittheilungen des Dr. Fritz Müller in Brasilien und nach eigenen Untersuchungen von Dr. Max Schulze. Abhandlungen der Naturforschenden Gesellschaft zu Halle 4 (1856–7): 19–38.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


Studying freshwater Planariae. Did CD find they had nervous systems?

News of T. C. Eyton and [William?] Owen.

Letter details

Letter no.
William Houghton
Charles Robert Darwin
Sent from
Wellington, Salop
Source of text
DAR 166: 271
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 5652,” accessed on 25 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 15