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Darwin Correspondence Project

To R. A. von Kölliker   14 June 1870

Down. | Beckenham Kent. S.E.

June 14. 1870.

My dear Sir.

I received two days ago from the Royal Soc: your extremely kind present of the Memoir on the Pennatuliden, with its numerous beautiful illustrations.1 Now that I see how you have worked on the subject, I am rather ashamed of having sent you my crude notes, at which you must have smiled.2

If you can spare a little time I should be very grateful for some information with respect to one of your former discoveries—3 Do you know whether the muscles to the quills of the porcupine, and those which raise and cause to vibrate the tail coverts of the Peacock, are striped or unstriped? Whatever they may be, I suppose that the same kind of muscles raise the plumes on the head, and the other plumes which many birds erect under excitement and as an ornament. If these muscles are striped, like those to the vibrissæ of the Carnivora (as is stated on your authority) do they occupy the same position and are they homologous with the unstriped muscles which move ordinary hairs? If this is the case all who believe in the evolution of species must I suppose admit that unstriped muscles can by some unknown means be developed into striped muscles.4 Can you believe in the possibility of such a process of development? I should be greatly obliged for a few words in answer; especially with respect to the muscles to the quills of the porcupine & to the plumes of such birds as the Peacock.

Permit me in conclusion to say how very much I was gratified & pleased at your little visit to Down5

With sincere respect. | Yours very faithfully | Charles Darwin.


CD probably refers to the first part of Kölliker’s paper, ‘Anatomisch-systematische Beschreibung der Alcyonarien: I. Die Pennatuliden’ (Anatomical-systematic description of the Alcyonaria: I. the Pennatulidae; Kölliker 1869–72). There is an offprint of the first part (Kölliker 1870) in the Darwin Library–Down.
See letter to R. A. von Kölliker, 18 April 1870 and n. 3.
CD refers to Kölliker’s isolation of ‘unstriped’ (smooth) involuntary muscles (Expression, pp. 100–1, Kölliker 1847).
See Expression, pp. 102–3.
Kölliker visited Down on 15 April 1870 (see letters from Albert Günther, [c. 9 April 1870] and 12 April 1870).


Expression: The expression of the emotions in man and animals. By Charles Darwin. London: John Murray. 1872.

Kölliker, Rudolf Albert von. 1847. Ueber die Struktur und die Verbreitung der glatten oder unwillkürlichen Muskeln. Mitteilungen der Naturforschenden Gesellschaft in Zürich 1: 18–28.

Kölliker, Rudolf Albert von. 1870. Anatomisch-systematische Beschreibung der Alcyonarien: I. Die Pennatuliden. Erste Hälfte. Frankfurt am Main: Christian Winter.


Thanks for RAvK’s work [Anatomisch-systematische Beschreibung der Alcyonarien, pt 1, Die Pennatuliden (1870)].

Asks whether muscles to quills of porcupine are striped. Are they homologous to muscles of ordinary hairs? Could unstriped muscles develop into striped?

Letter details

Letter no.
Charles Robert Darwin
Rudolf Albert von Kölliker
Sent from
Source of text
DAR 146: 22
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 7230,” accessed on 18 January 2022,

Also published in The Correspondence of Charles Darwin, vol. 18