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Darwin Correspondence Project

From George Busk   24 November 1871

32 Harley Str | London. | (W.C.)

24 day of Novr 1871

My dear Darwin

I am much obliged to you for the sight of Mr Gillman’s letter. I was not before aware that platycnemic tibiæ had been met with in America and am much interested in learning the fact.—1 I do not know whether you have seen a few remarks I made on this peculiarity as observed in some Welsh remains but if so you will find that I thought there was reason to believe that platycnemism was of two kinds—one of which was exemplyfied in the Gibraltar & Cro-Magnon tibiæ and the other in those fm Wales—2

I should therefore be very glad to learn which of the two forms was found in America—but to this point Mr Gillman does not refer. If you thought it worth while I would send him a copy of my paper.

The proportion of antero-posterior to transverse diameter given by him viz about .60—is very nearly the same as in the Welsh tibiæ and is Greater than in the Gibraltar bones & much greater than in the Cro-magnon tibiæ whose latitudinal index as I term it is not .60 as he supposes but .41 (1.1” to .45” The existence of this curious conformation so extensively among the priscan3 races in both hemispheres is very remarkable and well worthy of further enquiry. That it can hardly be considered in any way as indicative of a Simian tendency is, as it seems to me pretty clear from the circumstance that human platycnemic tibiæ have a lower latitudinal ridge than those of the Gorilla & Chimpanzee.4

Yours very truly | Geo Busk


Busk had been involved in the excavation of caves in Gibraltar in 1863, and in Denbighshire, Wales, in 1869, finding platycnemic bones (that is, flattened tibias) in both locations (see Busk 1868, and Dawkins and Busk 1870b). He described the two forms of platycnemia in Dawkins and Busk 1871, pp. 457–9. Copies of Busk 1868 and Dawkins and Busk 1870b are in the Darwin Pamphlet Collection–CUL. CD scored and excised passages on platycnemia in Busk 1868. See also letter from W. B. Dawkins, 27 August 1871.
Priscan: ancient, primitive (OED).
Busk argued that platycnemia was far more pronounced in human remains than in the tibia bones of gorillas and chimpanzees, and so it could not be a simian characteristic (Busk and Dawkins 1871, p. 459).


Busk, George. 1868. On the caves of Gibraltar in which human remains and works of art have been found. Transactions of the International Congress of Prehistoric Archaeology 3d session (1868): 106–66.

OED: The Oxford English dictionary. Being a corrected re-issue with an introduction, supplement and bibliography of a new English dictionary. Edited by James A. H. Murray, et al. 12 vols. and supplement. Oxford: Clarendon Press. 1970. A supplement to the Oxford English dictionary. 4 vols. Edited by R. W. Burchfield. Oxford: Clarendon Press. 1972–86. The Oxford English dictionary. 2d edition. 20 vols. Prepared by J. A. Simpson and E. S. C. Weiner. Oxford: Clarendon Press. 1989. Oxford English dictionary additional series. 3 vols. Edited by John Simpson et al. Oxford: Clarendon Press. 1993–7.


Thanks for information on platycnemic tibiae found in America. Believes the condition is of two kinds as exemplified by Gibraltar and Cro-Magnon tibiae on one side and the Welsh form on the other. Would like to know which of the two forms the American bones are; their proportions suggest they are very like the Welsh tibiae.

Letter details

Letter no.
George Busk
Charles Robert Darwin
Sent from
London, Harley St, 32
Source of text
DAR 160: 385
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 8084,” accessed on 29 January 2020,

Also published in The Correspondence of Charles Darwin, vol. 19