My dear Sir

I am very much obliged for your letter of the 23^d, & for your information on the wild Pigeons, which is of much value to me.— I enclose the stamps for the Rabbit, for which I heartily thank you, as it will prove interesting in comparison with some other insular individuals.—² You are so kind as to offer to take the great trouble of sending me some young Rock Pigeons: if I could have had them ten years ago, they w^d. have been worth their weight in gold to me, but now, I think, I could have hardly any chance of breeding them for a sufficient number of generations to make it worth while to have them; though this does not make it the less kind of your offering to send them.—³

About a month ago I wished extremely to ask you a question but I refrained solely because I thought I had already trespassed to a quite unreasonable degree on your kindness; but as you offer with so much goodnature to assist me further, I will ask my question, as I do not think it can cost very much trouble, & it is a point on which I have vainly sought for information.

In most parts of N. Europe, small horses or ponys are common (Eel-backs) of a Dun or Mouse-colour. Do such occur in the Shetlands? These duns generally, (perhaps always (?)) have a black stripe along the spine, & sometimes, (as I have seen) transverse dark Zebra-like marks on the legs, & I have been assured on perfect authority a transverse shoulder stripe like that of the Ass. Now any information on ponys of this colour w^d be of extreme interest to me, as it is a most widely geographically extended & ancient breed.—⁴

Is the spinal stripe universal with the duns? Have you ever seen the shoulder asinine stripe? are the transverse leg marks common? But especially I want to know whether these marks when they occur are plainer on the very young foal before the first hair is shed. And more than all I want to know whether the Dun or Mouse colour ever appears when neither parent is dun, and as far as known, no ancestor has been of this colour; though this must always be very doubtful.

Is the Dun (with spinal stripe & occasional other stripes) a very hereditary colour, ie will one parent of this colour generally transmit it, when two horses of different colours, one being dun, are crossed? When duns & other colours are crossed what colour results? I have written to Norway to beg for information;⁵ & if you can give me any (& coming from you, I know it will be reliable) it will in truth be of extreme use to me. Something analogous occurs in cream- & roan & chesnut horses; though in the two latter colours I have heard (& seen) only the spinal stripe. I do not know whether these colours ever appear in the Shetland herds.

I can trust only to your great kindness, so often shown to me, to forgive this long note, & I beg to remain, with hearty thanks, My dear Sir | Your’s sincerely | Ch. Darwin

Anything about the stripes on Chesnuts interests me almost as much as in Duns.