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Darwin Correspondence Project

From Robert Swinhoe   4 April 1864

British Consulate Taiwan. | Tamsuy.1

4 April, 1864.

Charles Darwin, Esqre My dear Sir,

I do not know whether your attention has ever been called to the peculiar breeds of Sheep found in Aden.2 The P. & O. Co ship them on board of their steam-ships for food, and on the passage out I had thus an opportunity of observing them. They are small, pie-bald (almost uniformly), and hairy— They have prominent faces like the Cape and Shanghai sheep, but have large dewlaps before & between the four legs like cows, and their tails are broad and fatty at the base with a short narrow tip bent suddenly downwards. The majority of the rams have no horns, but I saw one with short goat-like horns. I also saw among the herd a larger animal of a brown colour in most respects similar to the pie-bald race, but more goat-like. The hams of this sheep are thin and lanky. I also observed more lanky Indian sheep with flat faces and goat-like horns with brown slightly curled hair. In the face all these sheep are extremely goat-like, but differ in the form of the pupil of the eye from goats. The goats have an indistinct horizontal pupil over which the iris contracts and confuses its form. The sheep on the contrary have a narrow perpendicular pupil. I should think if properly studied by those you have the opportunity, the sheep of the tropics as compared with those of more northern climes, would somewhat assist the theory of transmutation by artificial selection.3

On the subject of usurpation by introduced races I saw some curious instances in Ceylon.4 Some 11 years ago I am told a Brazilian plant the Lantana mixta lost5 was introduced into the gardens of Ceylon. It has since become scattered through the country, and forms hedgerows for miles along the various roads even into Kandy, being also frequently found in patches on mountains 4000 feet high away from the road. Wherever it grows it spreads fast and seems to paralyse the rest of the plant life. It also occurs, but not so abundantly in the islands of Singapore & Penang.6

In all these three islands the Casuarina equisetorum of Australia has also been introduced and is become completely naturalised forming an important feature in the scenery. This tree grows to a good height, and is frequently covered over its trunk with various indigenous species of Ferns.7

There is only one other observation to trouble you with and then I have done. In describing a new species of Turdus the other day from the Formosan Mountains the Turdus albiceps mihi, I observed a prominent wart or tubercle on the carpal edge of its wing.8 This I thought curious and I immediately examined all the species of the group that I have in my present collection, to wit Oreocincla hancii, mihi Turdus pallidus, Gmel. Garrulax poecilorhynchus et ruficeps, Gould, and Garrulax taiwanus, mihi, all from Formosa, and I found the tubercle perceptible in a degree in them all. Now there is a species I am informed the Turdus dactylopterus, Bonaparte from Syria which has a prominent claw on its carpus.9 This then according to the theory expounded by you enables us to understand the existence of the wart in so many species of the same group. I suspect moreover that it occurs in a lesser or greater degree in all the members of the Turdidae, and I have drawn the attention of ornithologists to the fact through the pages of the “Ibis.”10

I continue at my leisure moments, as you perceive, my researches in Natural History, and I shall be much obliged to you if you can call my attention to any special objects, which I may have the preclusive opportunities to study in these parts for the information of others and for the advancement of science.

I remain | My dear Sir, | Your sincere friend & pupil, | Robert Swinhoe.

CD annotations

3.2 and is … Ferns. 3.4] double scored pencil *S1 !alignleft!CD note:11 *S2 Casuarina equisetum? from Australia naturalised & largely spread in Formosa & other islands Curious case of several Formosan Thrushes with excrescence on wings like the one known Syrian species.— Common descent?


Swinhoe had recently returned to Taiwan, also then known as Formosa, where he was vice-consul; he arrived at Tamsui on 31 January 1864 (see Ibis 6 (1864): 423 and P. B. Hall 1987). Tamsui, also known as Tanshui or Tansui (Columbia gazetteer of the world), which Swinhoe consistently referred to as ‘Tamsuy’, was the consular port of Taiwan, situated on the north-west coast.
In his letter of 7 March 1864, published in Ibis 6 (1864): 413–23, Swinhoe mentioned stopping at Aden, a major port on the south-east coast of Yemen (p. 414).
Swinhoe had sent CD information on animal breeding and variation on several occasions (see, for example, Correspondence vol. 10, letters from Robert Swinhoe, 12 November 1862 and n. 2, and 2 December 1862). CD discussed sheep and goats in regard to warm climates in Variation without referring to Swinhoe’s observations (see Variation 1: 97–9 and 2: 278, 302, 305–6).
CD discussed the naturalisation of non-native species in Origin, pp. 114–16 and 201–2; CD’s letters to Swinhoe have not been found, but CD often questioned his correspondents on this topic (see, for example, Correspondence vol. 11, letter to Julius von Haast, 22 January 1863).
Swinhoe here deleted the words, ‘(I enclose you a specimen)’.
The spread of Lantana mixta in Ceylon (now Sri Lanka) was described by Swinhoe in a letter of 7 March 1864, in Ibis 6 (1864): 413–23 (see p. 419). On his journey to Taiwan, he visited Ceylon, Penang (or Pinang), an island off the west coast of Malaysia, and Singapore (see Ibis 6 (1864): 418–22).
For Swinhoe’s discussion of Casuarina see Ibis 6 (1864): 419 and 421, where he refers to it as Casuarina equisetifolia, the Australian pine.
The tubercle in Turdidae was also referred to as an abortive wing-spur in Swinhoe’s description of the thrush Turdus albiceps in Swinhoe 1864, pp. 363–4 (see n. 10, below).
Swinhoe described Formosan species of thrush in Swinhoe 1863, pp. 51, 52, and 55–9 (with the spellings Garrulax taivanus and G. pœcilorhynchus, pp. 55 and 59). The Darwin Library–CUL contains an annotated reprint of Swinhoe 1863, bound with other papers published by Swinhoe in 1863, in a publisher’s case binding with the title on the spine ‘Formosa | R. Swinhoe’; the volume is inscribed to CD (see Marginalia 1: 797, and Correspondence vol. 11, letter from Robert Swinhoe, 29 July 1863 and n. 3). Swinhoe mentioned the Syrian thrush in Swinhoe 1864, p. 364 (see n. 8, above).
Swinhoe wrote that he had found the tubercle, or wart, on the carpal edge of the wing in many species in the group; he called the tubercle an ‘abortive wing-spur’ that had ‘acquired a full development’ in the Syrian species of Turdus (see Swinhoe 1864, p. 364). For CD’s discussions of rudimentary organs, see Origin, pp. 450–6; see also Correspondence vol. 11, letters to T. H. Huxley, 16 February [1863] and 27 June [1863].
See nn. 7–10, above.


Columbia gazetteer of the world: The Columbia gazetteer of the world. Edited by Saul B. Cohen. 3 vols. New York: Columbia University Press. 1998.

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

Hall, Philip B. 1987. Robert Swinhoe (1836–1877), FRS, FZS, FRGS: a Victorian naturalist in Treaty Port China. Geographical Journal 153: 37–47.

Marginalia: Charles Darwin’s marginalia. Edited by Mario A. Di Gregorio with the assistance of Nicholas W. Gill. Vol. 1. New York and London: Garland Publishing. 1990.

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.

Swinhoe, Robert. 1863a. The ornithology of Formosa, or Taiwan. Ibis 5: 198–219, 250–311, 377–435.

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


Reports on a strange breed of sheep at Aden,

a Brazilian plant naturalised in Ceylon,

the Australian Casuarina equisetum spreading in Taiwan,

and an excrescence on wing of several thrushes of Taiwan similar to a growth on wing of a Syrian species.

Letter details

Letter no.
Robert Swinhoe
Charles Robert Darwin
Sent from
British Consulate, Taiwan
Source of text
DAR 205.2 (Letters): 254–5
Physical description
4pp †, CD note

Please cite as

Darwin Correspondence Project, “Letter no. 4449,” accessed on 29 November 2021,

Also published in The Correspondence of Charles Darwin, vol. 12