To W. D. Fox 16 April 
Down Bromley Kent
My dear Fox
I want you to observe one point for me, on which I am extremely much interested & which will give you no trouble beyond keeping your eyes open, & that is a habit I know full well that you have.
I find Horses of various colours often have a spinal band or stripe of different & darker tint than rest of body—rarely transverse bars on legs, generally on under side of front legs—still more rarely a very faint transverse shoulder stripe, like an ass.—
Is there any breed of Delamere Forest Ponies.—1 I have found out little about Ponies in these respects. Sir P. Egerton has, I believe, some quite thorough bred Chesnut horses:2 have any of these the spinal stripe. Mouse-coloured ponies or rather small horses, often have spinal & leg bars. So have Dun Horses (by Dun I mean real colour of cream mixed with brown bay or chesnut).— So have sometimes Chesnuts, but I have not yet got case of spinal stripe in Chesnut Race Horse, or in quite heavy Cart-Horse.—3 Any facts of this nature of such stripes in Horses would be most useful to me.— There is parallel case in legs of Donkey & I have collected some most curious cases of stripes appearing in various crossed equine animals.—4
I have, also, large mass of parallel facts in the breeds of Pigeons about the wing-bars.—5 I suspect it will throw light on colour of primeval Horse. So do help me if occasion turns up.— I have not yet returned your Oology, though I have finished with it; for I have not been in London since, & I did not like to intrust it to Carrier; though perhaps I had now better do so.—6 My health has been lately very bad from overwork & on Tuesday I go for fortnights Hydropathy.7 My work is everlasting.
Farewell— My dear Fox, I trust you are well | Farewell | C. Darwin
Asks WDF for facts about stripes in horses and ponies.
Health has been very bad.
Please cite as
Darwin Correspondence Project, “Letter no. 2256,” accessed on 28 September 2016, http://www.darwinproject.ac.uk/DCP-LETT-2256