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.