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Darwin Correspondence Project

To William Turner   15 January [1867]1

Down. | Bromley. | Kent. S.E.

Jan. 15th.

My dear Sir

As you were so kind as to say that I might ask you a few more questions, & as my wishes are now rather more definite, I do so now;2 but you must not suppose that I am in any hurry for an answer.

(1) One or two good cases of any rudiment of a muscle, would suffice (I have lost one good case which I copied from some French writer): if any muscle in our arms exists in a rudimentary or nearly rudimentary condition, & which would be of service to a quadruped, going on all fours; such case would perhaps be best.3

(2) You reminded me that there were two sets of muscles for moving the whole ear & its parts; which of such muscles are rudimentary in human ear?4

(3) I have used your information (from Theile etc) about muscles to Os Coccyx:5 if my memory does not deceive me, those 4 coccygeal bones contain spinal marrow at an early embryonic age, & afterwards it retreats. If this is so, are vestiges of membranes of spinal marrow retained?6

(4) I have given case of Prostate gland (to which you allude in one of your papers) as a rudiment or representation of the Uterus.7 I am sure I have read (& hope to find the reference,) some recent observations of the existence of both testes & ovaria at early embryonic age in both sexes of the higher animals.8 Do you know anything on this head?

(5) Is any other gland rudimentary in mankind, besides the mammary glands in male mammals?9

(6) I may add that I have alluded to traces of the supra-condyloid foramen in humerus of man;10 & to the nictitating membrane. By the way do you chance to remember whether the nictitating membrane is well developed in Marsupials?11

Pray forgive me, if you can, for being so very troublesome, & believe me, my dear Sir | Yours sincerely obliged | Ch. Darwin


The year is established by the relationship between this letter and the letter to William Turner, 1 February [1867].
CD met Turner at a reception at the Royal Society of London on 28 April 1866, and had since received papers from him (see Correspondence vol. 14). Turner and CD did correspond in 1866, but Turner’s letters have not been found (Correspondence vol. 14).
CD may be referring to a paper on rudimentary muscles in the foot and hand by Adolphe Richard (Richard 1852), which he cited in Descent 1: 19 n. CD had long been interested in rudimentary organs (see Origin, pp. 450–6). He was currently working on his ‘Essay on man’, which he was considering adding to Variation, but which ultimately became part of Descent and Expression (see letter to John Murray, 3 January [1867] and n. 5, and ‘Journal’, Appendix II).
The letter containing Turner’s statement on the muscles of the ear and Turner’s reply to this letter have not been found. CD wrote in Descent 1: 20–1 that all the muscles moving the ear were in a rudimentary condition in humans; he did not cite Turner.
In Descent 1: 29–30, CD wrote that he had been informed by Turner that one of the associated rudimentary muscles of the os coccyx had been described by Friedrich Wilhelm Theile ‘as a rudimentary repetition of the extensor of the tail’, which was ‘so largely developed in many mammals’. Theile made this statement in Theile 1839. For CD’s earlier queries to Turner on the coccyx, see Correspondence vol. 14, letter to William Turner, 14 December [1866]. CD had suspected for some time that muscles were attached to the os coccyx and that it was a rudimentary tail (see Correspondence vol. 7, letter to Charles Lyell, 11 October [1859]).
CD mentioned the vestige of the spinal cord in the os coccyx in Descent 1: 30, citing Turner as the source for the information.
CD referred to the male prostate gland as a rudiment or ‘homologue’ of the female uterus in Descent 1: 31, but cited Leuckart 1852, an article he had been alerted to in 1861 (see Correspondence vol. 9, letter from George Rolleston, 16 April 1861). CD cited Turner’s article on the prostate gland (Turner 1865) in his chapter on development in Descent 1: 123–4. A lightly annotated copy of an offprint of Turner 1865 is in the Darwin Pamphlet Collection–CUL.
CD mentioned in Descent 1: 207 that at an early embryonic period both sexes of vertebrates possess male and female reproductive glands, and discussed the possibility of a progenitor of the vertebrates having been hermaphrodite or androgynous; he cited Gegenbaur 1870 on this point.
CD noted the rudimentary mammary glands in male mammals in Descent 1: 30–1 and 209, citing information from Turner on page 209.
In Descent 1: 28, CD wrote that sometimes the trace of a passage near the lower end of the humerus (bone of upper arm) was apparent in humans; he stated that the fact that, when it was present, the ‘great nerve’ invariably passed through it indicated that it was ‘the homologue and rudiment of the supra-condyloid foramen of the lower animals’; CD added that Turner estimated that it occurred in about one per cent of recent human skeletons.
The rudiment of the nictitating membrane in humans was mentioned by CD in Descent, as was the fairly well-developed nictitating membrane in monotremes and marsupials (Descent 1: 23); however, CD did not cite Turner on these points. See also Descent 1: 207.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 28 vols to date. Cambridge: Cambridge University Press. 1985–.

Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

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

Leuckart, Rudolf. 1852. Vesicula prostatica. In vol. 4 of The cyclopaedia of anatomy and physiology, edited by Robert Bentley Todd. London: Longman, Brown, Green, and Longmans.

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.

Richard, Adolphe. 1852. Essai sur l’anatomie philosophique et l’interprétation de quelques anomolies musculaires du membre thoracique dans l’espèce humaine. [Read 26 January 1852.] Annales des sciences naturelles (zoologie) 3d ser. 18: 5–20.

Theile, Friedrich Wilhelm. 1839. Entdeckung von Muskeln, welche die Rückenwirbel drehen (Rotatores dorsi) beim Menschen und den Säugethieren, nebst Bemerkungen über die Processus transversi und obliqui und über die Rückenmuskeln. Archiv für Anatomie, Physiologie und wissenschaftliche Medizin (1839): 102–38.

Turner, William. 1865. On some malformations of the organs of generation. Edinburgh: Oliver and Boyd.

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


Requests information about rudimentary muscles and organs in man. Asks about marrow of os coccyx, and about testes and ovaria in early embryos of both sexes.

Letter details

Letter no.
Charles Robert Darwin
William Turner
Sent from
Source of text
Edinburgh University Library, Centre for Research Collections (Dc.2.96/5 folio 2)
Physical description
ALS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 5362,” accessed on 25 June 2022,

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