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Darwin Correspondence Project

To W. H. Flower   25 March [1870]1

Down Beckenham | Kent

Mar 25

My dear Mr Flower

I am much obliged to you for having sent me yr Lecture, of which I had heard & was anxious to see. It strikes me as in every way very good & very well written. I am sure I feel much obliged to you for the highly honourable manner in which you mention my name.2

The feet of the Koala & Kangoroo is one of the most beautiful cases I ever heard of.3 Such facts will do more to convince unbelievers than pages of general reasoning. I am glad you noticed the curiously false argument in the Month about the teeth of the dog & Thylacinus: I had selected this in my M.S. as an excellent instance of analogical resemblance.4 I cd have answered, I think satisfactorily, many of the objections advanced in this article; but my whole time wd be wasted if I once began to answer objectors.

With very sincere thanks for the great interest & instruction which you have afforded me Pray believe me | yours very sincerely | Ch. Darwin P.S.How curiously inaccurate the author of article in “The Month” is in some respects— He speaks of similarity of teeth of Thylacinus & Canis as being so great as to bespeak community of descent, & what a profound difference in essential nature in incisors & premolars & molars!5

How odd with the giraffe— but it is not worth writing.—


The year is established by the reference to Flower 1870; see n. 2, below.
Flower had given the introductory lecture to the course of comparative anatomy at the Royal College of Surgeons on 14 February 1870; it was published in the Medical Times and Gazette for 19 February (Flower 1870). Flower mentioned CD along with Alfred Russel Wallace as the originators of the theory of the origin of species by means of natural selection (Flower 1870, p. 196).
In Origin 6th ed., p. 382, CD cited Flower for the information that the hind feet of the kangaroo, the koala, and the bandicoot were constructed on the same plan, despite being used for different purposes. See also Flower 1870, pp. 197–8.
The July 1869 issue of the Month included the first part of an anonymous article by St George Jackson Mivart ([Mivart] 1869) titled ‘Difficulties of the theory of natural selection’. The author argued (p. 49): Nothing can be more remarkable than the identity of structure between certain of the teeth of the large predatory marsupial called the thylacine, or Tasmanian wolf, and those of the common dog. The resemblance is so complete that community of descent is at once most forcibly suggested, and yet on the assumption adopted, the thylacine may be closely related genetically to the kangaroo and its allies, but must be separated from the dog by an abyss. In the sixth edition of Origin, published in 1872, CD commented (p. 374): Numerous cases could be given of striking resemblances in quite distinct beings between single parts or organs, which have been adapted for the same functions. A good instance is afforded by the close resemblance of the jaws of the dog and Tasmanian wolf or Thylacinus,—animals which are widely sundered in the natural system. But this resemblance is confined to general appearance, as in the prominence of the canines, and in the cutting shape of the molar teeth. CD added that Flower had come to the same conclusion (ibid., p. 375). See Flower 1870, p. 199.
Thylacinus is a genus of marsupials which had one extant species in the 19th century, T. cynocephalus, the Tasmanian wolf or thylacine. The species dentition differed from that of Canis in many respects (see Jones and Stoddart 1998). It became extinct in the 1930s.


Flower, William Henry. 1870. Introductory lecture to the course of comparative anatomy … at the Royal College of Surgeons. [Read 14 February 1870.] Medical Times and Gazette 40: 195–200.

[Mivart, St George Jackson.] 1869. Difficulties of the theory of natural selection. Month 11: 35–53, 134–53, 274–89.

Origin 6th ed.: The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 6th edition, with additions and corrections. By Charles Darwin. London: John Murray. 1872.

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.


Thanks WHF for his very good lecture.

Letter details

Letter no.
Charles Robert Darwin
William Henry Flower
Sent from
Source of text
John Innes Foundation Historical Collections; DAR 270.1: 24
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 7148,” accessed on 17 September 2021,

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