skip to content

Darwin Correspondence Project

From Edward Blyth   6 February 1868

7 Princess Terrace, | Regent’s Pk,

Feby. 6/68.

My Dear Sir,

I am exceedingly obliged to you for the copy of your new work, about which I shall have many remarks to make, as I can find time to write them, some of which may be useful for the next edition.1 As regards the mule canaries, since I wrote to you about them, I have seen some dozens of goldfinch-mules, without finding a single exception to the rule of their having streaked plumage.2 I now send an extract from a newspaper bearing on the subject of hereditariness in the matter of fecundity.3

I think you notice the prolificacy of the small Chinese sheep formerly in the Z.G.—4 The common small goats of Bengal have commonly four kids at a birth. The same breed to all appearance is figured as African (I think from Guinea?) by Fred. Cuvier.5 About merinos, I have just cut the following passages about merinos from two Australian newspapers.

1. “Every squatter or wool-grower would acknowledge that the fleece of the merino sheep was greatly superior to that of the Cotswold; yet exactly 400 years ago, Edward IV of England presented King John of Arragon6 with twenty Cotswold ewes and four rams, and they were the progenitors of the present merino sheep”— I want information concerning the flocks of black sheep on the Pyrenees, & in Spain and Sardinia. Are they not descendants of O. musimon, with crescentic horns and short tail, like the Shetland race figured by Lowe, which is the same as the old Highland race.7 There are two breeds of merinos with glossy wool, one obtained by means of selection in Lincolnshire, while it is stated of a French breed—

2. “The Mauchamp variety of the merino was raised from a lamb born with bright smooth hair instead of wool, such as has no doubt been often seen in other flocks, but quietly got rid of as an eyesore; and the descendants of this lamb have since been crossed with both fine and coarse woolled sheep, imparting to all the desired quality of brightness of staple, and this without any one of the race having been subjected to such a combination of circumstances as gave rise to the peculiarity in England”. The last remark merely refers to the climate &c of Lincolnshire.8 The remarks on pedigree wheat, as grown in Australia, will doubtless interest you.9 About unequal developments of the two sides of the body (Vol. II, 53), you might have noticed the skulls of Cetacea (with the only exception known to me of Platanista),10 & to the best of my recollection the greater development is always on the same side? How about the developed tusk of the Narwhal,11 And lower tusk of adult male Mastodon ohioticus?12 and again the whalers assert that the vision of the cachelot is always defective on one side, so that they endeavour to get at the blind side of their quarry!13 Among crustaceans, the males only of the Gelasimus crabs have one claw preposterously developed, which I have observed to be as often the right one as the left; whereas in Ocypoda I think that it is almost constantly on one side.14 How, too, about the two very different claws of the common lobster?

I sincerely congratulate you on the success achieved by your son at Cambridge.15

Yours most truly, | E. Blyth

CD annotations

1.3 next] underl pencil; ‘no’ added pencil
1.4 goldfinch] underl pencil
1.6 newspaper … fecundity. 1.6] double scored pencil; ‘X’ added pencil
3.3 Edward … sheep”— 3.4] scored pencil; ‘no’ added pencil
4.14 Among … side. 4.17] double scored pencil


Blyth refers to Variation; his name appears on CD’s presentation list for the book (see Correspondence vol. 16, Appendix IV).
The newspaper extract has not been found.
In Variation 1: 97–8, CD mentioned the ‘Shangai sheep … lately exhibited in the Zoological Gardens’ of London as a remarkable instance of the variability of fecundity between breeds, with some sheep producing twins or triplets.
Blyth refers to Frédéric Cuvier, and to the ‘bouc et chèvre nains’ illustrated in E. Geoffroy Saint-Hilaire and Cuvier 1824–47, vol. 1; their probable origin is given as Africa, and they are described as resembling a goat found in Calcutta. CD discussed goats in Variation 1: 101–2.
Edward IV was king of England from 1461 to 1483; John II was king of Aragon from 1458 to 1479.
Ovis musimon (now O. aries, the mouflon) is the ancestor of the domestic sheep (Wilson and Reeder eds. 1993). The reference is to Low 1842, vol. 2, pl. 1 (‘Ram of the ancient breed, from the Isle of Enhallow’).
CD mentioned the ‘Mauchamp-merino’ in Variation 1: 100–1, and noted the effect of soil, climate, and pasturage on local breeds in Britain in ibid., p. 96.
CD discussed the effects of cultivation and of local conditions on the production of varieties of wheat in Variation.
CD discussed unequal development in the left and right sides of animals and plants as an example of latent characters in Variation 2: 53. Cetacea is the order that includes whales, dolphins, and porpoises. Platanista is a genus of river dolphins, comprising two species native to the river systems of South Asia (Nowak 1999, pp. 900–2).
The left tooth in male narwhals (Monodon monoceros) grows in a spiral pattern into a long tusk (Nowak 1999, pp. 909–11).
Mastodon ohioticus (now Mastodon americanus, the American mastodon), an extinct species whose fossil remains were found in North America, is described in Falconer 1868, 1: 45, 49, 55–68.
Cachelot is the French common name of Physeter catodon, the sperm whale.
Gelasimus (now Uca, fiddler crabs) and Ocypoda (now Ocypode, ghost crabs) were both discussed in F. Müller 1864. CD discussed the chelae (pincers) of male crustacea in Descent 1: 330, noting that in many species, including Gelasimus, those on opposite sides of the body were unequal in size. See also letter from C. S. Bate, 24 May 1868.
George Howard Darwin had achieved second place in the final examination of the mathematical tripos at Cambridge (Cambridge University calendar 1868).


Cambridge University calendar: The Cambridge University calendar. Cambridge: W. Page [and others]. 1796–1950.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 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.

Falconer, Hugh. 1868. Palæontological memoirs and notes of the late Hugh Falconer … with a biographical sketch of the author. Compiled and edited by Charles Murchison. 2 vols. London: Robert Hardwicke.

Low, David. 1842. The breeds of the domestic animals of the British Isles. 2 vols. London: Longman, Orme, Brown, Green, & Longmans.

Nowak, Ronald M. 1999. Walker’s mammals of the world. 6th edition. 2 vols. Baltimore and London: The Johns Hopkins University Press.

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


Discusses the origin and characters of sheep breeds, particularly the merino.

Reports observations on reversion to wild type in canary mules

and lists some animals that show a unique development restricted to one side of their bodies.

Letter details

Letter no.
Edward Blyth
Charles Robert Darwin
Sent from
London, Princess Terrace, 7
Source of text
DAR 160: 212
Physical description
4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 5845,” accessed on 17 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 16