In your note you speak of sexual selection and protection as sufficient to account for the colouring of all animals; but it seems to me doubtful how far this will come into play with some of the lower animals, such as sea anemones, some corals, etc. etc. On the other hand, Haeckel has recently well shown that the transparency and absence of colour in the lower oceanic animals, belonging to the most different classes, may be well accounted for on the principle of protection. Some time or other I should like much to know where your paper on the nests of birds has appeared, and I shall be extremely anxious to read your paper in the _Westminster Review_. Your paper on the sexual colouring of birds will, I have no doubt, be very striking. Forgive me, if you can, for a touch of illiberality about your paper, and believe me yours very sincerely, CH. DARWIN. * * * * * _Down, Bromley, Kent, S.E. July 6, 1867._ My dear Wallace,--I am very much obliged for your article on Mimicry,[61] the whole of which I have read with the greatest interest. You certainly have the art of putting your ideas with remarkable force and clearness; now that I am slaving over proof-sheets it makes me almost envious. I have been particularly glad to read about the birds' nests, and I must procure the _Intellectual Observer_; but the point which I think struck me most was about its being of no use to the Heliconias to acquire in a slight degree a disagreeable taste. What a curious case is that about the coral snakes. The summary, and indeed the whole, is excellent, and I have enjoyed it much.--With many thanks, yours very sincerely, CH. DARWIN. * * * * * _9 St. Mark's Crescent, N.W. Wednesday, [August or September, 1867]._ Dear Darwin,--I am very sorry I was out when you called yesterday. I had just gone to the Zoological Gardens, and I met Sir C. Lyell, who told me you were in town. If you should have time to go to Bayswater, I think you would be pleased to see the collections which I have displayed there in the form of an _exhibition_ (though the public will not go to see it). If you can go, with any friends, I should like to meet you there if you can appoint a time. I am glad to find you continue in tolerable health.--Believe me yours very faithfully, ALFRED R. WALLACE. What do you think of the Duke of Argyll's criticisms, and the more pretentious one in the last number of the _North British Review_? I have written a little article answering them both, but I do not yet know where to get it published.--A.R.W. * * * * * _76-1/2 Westbourne Grove, Bayswater, W. October 1, 1867._ Dear Darwin,--I am sorry I was not in town when your note came. I took a short trip to Scotland after the British Association Meeting, and went up Ben Lawers. It was very cold and wet, and I could not find a companion or I should have gone as far as Glen Roy.