From Edward Blyth 11 February 1868
7 Princess Terrace, Regent’s Pk, N.W.
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. livia—18 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 vulgaris— Pavo 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.
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.
Please cite as
Darwin Correspondence Project, “Letter no. 5861,” accessed on 18 January 2017, http://www.darwinproject.ac.uk/DCP-LETT-5861