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Darwin Correspondence Project


From Edward Blyth   11 February 1868

7 Princess Terrace, Regent’s Pk, N.W.

Feby. 11/68—

My dear Sir,

I am glad to learn that your book is at once to enter upon a new edition, because there are a few things that must be altered.1 With reference to Crustacea, I find that in lobsters the molar claw is indifferently placed to the right or left, as I know to be also the case with Gelasimus, & I am probably wrong in my impression that the claws of Ocypoda are otherwise.2 The Cetacea, I think, I can confidently assert, are always deficient on the same side, and so with the developed ovary of birds, which (according to my experience) is invariably the right one. I believe that you are right about the object of the immense claw of Gelasimus, but can give you no facts from personal observation.3 Sometimes the human conformation is reversed, the heart pointing to the right & the great lobe of the liver being on the left. Some shells, I am told, begin sinistral and then turn dextral! Have you thought of the nursing of children as more especially developing the right limb, & sometimes the left one? Has the inequality of Cetacea anything to do with the side of lactation? (Bartletts’s suggestion).4 You call the musk duck Dendrocygna arborea. It should be Cairina moschata. The former is a widely different species and [even] genus.5 I wholly doubt, & Bartlett agrees with me, that there is any satisfactory cross known of a dog with the fox. So far as I can learn, and I have seen the little fennec copulate, there is no tie in the coitus of the foxes, unlike wolves and jackals! Again, neither Bartlett nor I believe in the leporines. There is a hare-like breed of true rabbit common in the south of France, with which the ordinary rabbit has been crossed, a fertile race between hare and rabbit.6 I will not bore you with unnecessary facts, but there are a few of your statements that I feel justified in commenting upon, though in a future letter. Of course you have read the Duke of Argyll’s book,7 & therefore his remarks on the absolute persistence of specific differences in some 400 species of Trochilidæ. But he derives his alleged facts from Gould,8 who I fear is an unsafe guide, who in falcons, &c, rejects intermediate specimens. Thus his specimens of the three races of gir falcon appear very distinct, but I have reason to believe that the gaps between them might be filled up!9 However, there are groups of animals, as well as of plants, in which the specific distinctions are underterminable. While the specific distinctions of the very numerous Cercopitheci of Africa hold wonderfully true, the reverse is the case with the Cebi of South America, all or most of which seem to grade into each other.10 So with the curassows among birds,11 & to a considerable extent many of the Salmonidæ among fishes. Just the case of Rosa, Rubus, Hieracium, Potentilla, Salix, &c. Putting aside two or three well marked species of bears, as maritimus, labiatus, malayanus, most of the Ursi seem to be much in the same predicament.12 That name Sus indicus is most unfortunate, and I cannot help thinking that the Sus leucomystax of Japan (& of Formosa) is the true wild type of this form.13 About Potamochærus penicillatus, Gray has lately shewn that this is the true S. porcus, L. &, as well as the S. guianiensis of the old authors.14 I wholly disagree with you that the Numida ptilorhyncha of Eastern Africa is the true original type of the domestic guinea-fowl.15 As regards Gallus ferrugineus (v. bankiva), you have not seen my remarks on this bird in the Ibis (commentary on Jerdon’s book).16 Are you aware that the game fowls of India & the Malay countries are totally different from our game-fowls, heavy and thick in the leg, & inelegant to my eye, though with inveterate pluck, & too heavy for our form of gamecock, which they would be an overmatch for, as remarked by Crawford.17 These are a few remarks which occur to me offhand, & I do not wish to bore you, as I said before, with unnecessary ones, but it will not take up much of my time to say what I wish to say.

Yours very truly, | E. Blyth.—

Do not trouble yourself to reply to this.

P.S. If 〈the〉 foregoing remarks read somewhat curt and didactic, they are so merely for the sake of brevity.— Races of wild common fowl—less distinct and separable even than those of wild Col. livia18 the tame certainly not less clearly derived from the former, one and all— Domestic fowls represented on Nineveh signets regular dunghills, those on Xanthian frieze differing in no apparent respect from jungle fowl,19 like those now wild in Tahiti, where anciently introduced, as doubtless also in Philippines.— Geographical Races of wild common fowl not more distinct and separable than those of Perdix cinerea or P. saxatilis, or of Francolinus vulgarisPavo spiciferus of Java much more brightly coloured than the same species in Burma.—20 Bartlett tells me that he can distinguish Dutch examples of Perdix cinerea in the London markets at the first glance, the markings being coarser.— Slow growth of wild animals as compared with domestic strikingly illustrated by those 〈    〉 Two young Sus andamanensis in the Z.G. still less than half-grown, though six months old or thereabouts.21 The different 〈    〉 Indian cattle— gauras, frontalis, sondaicus—exceedingly slow growers—22 Fat-tailed & fat-rumped sheep. Look at the carcasses of fat ordinary sheep in the butchers’ shops, & you will see the strong tendency in them to deposit fat about the base of the tail or caudal region. Selection in breeding would probably soon develop a steatopygous race here!— Puppies of the most widely differing races of Dogs remarkably similar for some weeks after birth. This I have been noticing in Bartlett’s litter of Italian greyhounds. This Itn. greyhound bitch first crossed with a toy terrier, next put to her own race, and one remarkably diminutive puppy (purely greyhound bred) unquestionably resembles the toy terrier which is not its sire.

CD annotations

1.1 I am … dextral! 1.11] crossed pencil
2.3 on the absolute … underterminable 2.9] crossed pencil
2.9 While … each other. 2.11] scored red crayon
2.12 many of the Salmonidæ … to say. 3.3] crossed pencil
6.1 P.S. … sire. 6.22] ‘Blyth Feb. 12. 1868.’ added ink
6.8 Perdix … glance, 6.11] scored red crayon
6.12 strikingly … shops 6.16] scored red crayon; ‘Wild animals slow growing’ added ink
6.18 Puppies … sire. 6.22] crossed red crayon


Blyth’s comments in this letter are in reply to a letter from CD that has not been found. A second printing of Variation was published in February 1868, incorporating a few additions and corrections. This was not considered a second edition (see Freeman 1977).
See letter from Edward Blyth, 6 February 1868 and nn. 10 and 14.
CD later stated that the main use of the chelae in male Gelasimus (now Uca) was ‘to seize and secure the female’ (Descent 1: 331).
Abraham Dee Bartlett.
Dendrocygna arborea (family Dendrocygnidae, the West Indian whistling-duck) is found in the Caribbean. Cairina moschata (family Anatidae, the muscovy duck) is native to Central and South America, and has been domesticated in Europe and elsewhere (Ojasti 1996). CD refered to the muscovy duck as the ‘musk-duck’. In the first printing of Variation 1: 181, CD gave the name Dendrocygna viduata (the white-faced whistling-duck, found in Africa and South America); this was changed to Anas moschata in the second printing of the first edition, and to Cairina moschata in Variation 2d ed., 1: 191.
In Variation, CD mentioned an alleged new breed, called ‘leporides’, produced in France by crossing the hare and the rabbit; he added, however, that the breed was incapable of reproducing (Variation 1: 105, 2: 98–9).
Blyth refers to the Reign of law by George Douglas Campbell, the eighth duke of Argyll (Campbell 1867). CD’s annotated copy is in the Darwin Library–CUL (see Marginalia 1: 18). For CD’s views of the book, see Correspondence vol. 15.
Campbell 1867, pp. 251–2, contains the following passage from John Gould’s An introduction to the Trochilidæ (J. Gould 1861, p. 5): It might be thought by some persons that 400 species of birds so diminutive in size, and of one family, could scarcely be distinguished from each other; but any one who studies the subject, will soon perceive that such is not the case.... What we designate a species has really distinctive and constant characters; and in the whole of my experience, with many thousands of Humming-Birds passing through my hands, I have never observed an instance of any variation which would lead me to suppose that it was the result of a union of two species.
Blyth refers to the falcons in Gould’s Birds of Great Britain (J. Gould 1873, vol. 1; the book was published in twenty-five parts from 1863). Gould described Falco islandus (the Iceland falcon), Falco candicans (the Greenland falcon), and Falco gyrfalco (the Norwegian or gyrfalcon), as distinct species. The birds are now classed as a single species, Falco rusticolus. It is polymorphic, with three colour phases (white, grey, and dark), and is also sexually dimorphic, with females nearly twice as large as males.
Cercopithecus is a genus of Old World monkeys. Cebus is a genus of capuchin monkeys.
Curassow is a common name for the bird genus Crax.
Blyth refers to Ursus maritimus, the polar bear; U. labiatus the Indian black bear; and U. malayanus (now Helarctos malayanus), the sun bear.
CD discussed Sus indicus, a name applied to many domestic breeds of pig, whose wild ancestor was unknown, in Variation 1: 65–70. He remarked: ‘This name … is an unfortunate one, as the wild aboriginal does not inhabit India, and the best-known domesticated breeds have been imported from Siam and China’ (ibid., p. 65). Blyth discussed S. leucomystax as the possible ancestor of the Chinese domestic pig in Land and Water, 16 February 1867.
Potomochoerus penicillatus, Porcus guineensis, and Sus porcus, Linn., are listed as synonyms of Potamochoerus porcus (the red river hog) in Gray’s revised taxonomy of the pig (see J. E. Gray 1868, p. 36). CD had mentioned P. penicillatus in Variation 2: 150.
CD had stated that the domesticated guinea-fowl was believed by some naturalists to be descended from Numida ptilorhynca in Variation 1: 294. Numida ptilorhynca is now N. meleagris, the helmeted guineafowl; it has been widely domesticated.
CD discussed the wild Gallus ferrugineus (or G. bankiva, now G. gallus, the red junglefowl) as the possible ancestor of domestic fowl in Variation 1: 226–7, 233–46. He cited Thomas Claverhill Jerdon on this point (ibid., p. 237 n. 25). Blyth’s commentary on Jerdon 1862–4 appeared in Ibis in 1866 and 1867; for the section on G. ferrugineus, see Blyth 1866–7, 3: 154–7.
John Crawfurd described the domestic and game cocks of Malay and India as larger and more powerful than European breeds in A descriptive dictionary of the Indian islands & adjacent countries (Crawfurd 1856, p. 113).
CD had argued that all domestic pigeon breeds descended from the wild Columbia livia (see Origin, pp. 23–4, and Variation 1: 134, 180–224).
A dunghill fowl is a common barndoor fowl, as distinguished from the game-cock (OED). There is a Xanthian frieze depicting cocks and hens in the British Museum (see Pryce 1928, pp. 137–9).
Perdix cinerea is now P. perdix (the common or grey partridge); P. saxatilis is now Alectoris graeca saxatilis, a subspecies of A. graeca (the rock partridge); Francolinus vulgaris is now Francolinus francolinus (the black francolin); Pavo spiciferus is now P. muticus (the green peafowl). Two subspecies of green peafowl are currently found in Burma: P. m. spificer and P. m. imperator. The Javanese peafowl is P. muticus muticus. All of these species are in the family Phasianidae. See Clements 2000.
Living specimens of Sus andamenensis from the gardens of the Zoological Society at Regent’s Park, London, are mentioned in J. E. Gray 1868, p. 30.
Bos gauras is now B. frontalis gauras, the Indian gaur; B. sondaicus is now Bos javanicus, the banteng. On species of Indian cattle, see D. E. Wilson and Reeder 2005.


Corrects some facts and gives further information on some points for the 2d ed. of Variation.

Specific distinctions among animals.

Cercopithecus of Africa contrasted with the Cebus of South America.

Notes on domestic fowls and their ancestors.

Slow growth of wild animals compared with domestic varieties.

Letter details

Letter no.
Blyth, Edward
Darwin, C. R.
Sent from
London, Princess Terrace, 7
Source of text
DAR 80: B169a–c
Physical description
6pp †

Please cite as

Darwin Correspondence Project, “Letter no. 5861,” accessed on 30 August 2016,