Promises to send coral specimens.

Thanks MW for his essay [Die Darwin’sche Theorie und das Migrationsgesetz der Organismen (1868)]. Is highly gratified that MW agrees with him to a considerable extent.

Almost wishes that he could believe in the importance of isolation to the same extent as MW.

Gives Charles Bell’s explanation of the contraction of the orbicularis during screaming and seeks confirmation of his view because the action is "the key-stone of a whole class of expressions". Curious to learn WB’s conclusion in regard to the relation between contraction of the orbicularis and secretion of tears. Notes that voluntary contraction of the orbicularis causes no tears.

Thanks JB for his information. Has heard of analogous cases to JB’s observations on [colours of] crossed rats; the offspring of white and grey mice are stated to be either white or grey and never piebald.

Movement in plants.

Dimorphism.

Would welcome FM’s opinion of Pangenesis.

Asks for [John?] Smith’s exact count of seeds of the crossed and self-fertilised Victoria water-lily. Similar question on Euryale seed and seedlings.

JDH’s coming [BAAS] Presidential Address.

CD thanks JJW for the mine of information his last "ten!" letters contain. Comments on sexual display of pheasants and colour preferences of pigeons.

Asks about hens that pair earliest in spring and about possible existence of unpaired birds.

Glad to hear about colours of Hylobates.

Cannot find any statement about which digits in man are most subject to syndactylism in Isidore Geoffroy [Saint-Hilaire]’s Histoire des anomalies [1832–7].

Asks questions concerned with seasonal and sexual changes in plumage of various bird species.

Does male woodpecker share in incubation?

More on the "terrible problem" of natural selection and sterility. CD’s reasons for disagreeing with ARW. CD analyses and answers ARW in detail in defence of his conclusion that sterility cannot be increased through natural selection.

Thanks Charles Langstaff for his observations relating to expression. Has requested observations on the platysma. Discusses the actions of other facial muscles, especially during crying. [Encloses 5828.]

Warns ARW of dubious character of list of European alpine genera and species in volcanoes of Hawaii. Problems of geographical distribution in oceanic islands.

BDW’s letter [6051?] and his notes are a "mine of wealth". The negative evidence is of much value. Sexual selection is a perplexing subject – finds he "must make the best of a rather bad job".

Sends copy [of Variation].

Asks JM to send Variation to G. Boccardo in Italy.

Sends title (suggested by Lyell) for translation of Fritz Müller’s Für Darwin (which Dallas is translating). CD does not wish to go to great expense in advertising it.

Has tried using dealers’ price-lists as a guide to sex ratios in Lepidoptera; finds numerous cases in which the sexes bring different prices and in virtually all of them the males are cheaper. This seems to confirm the impression of the field collectors.

Wishes RT good luck with natural history in S. Africa.

About the advertising and title of a book [the translation of Fritz Müller’s Für Darwin, see 6114].

CD has questions related to colour differences in the sexes of butterflies, especially in relation to HWB’s paper ["On variation in sexes of Argynnis diana", Proc. Entomol. Soc. Philadelphia 4 (1865): 204–7].

Mentions that his MS on Lepidoptera [for Descent] is longer than he intended and the information is four-fifths owed to HWB.

Admires ARW’s "Theory of birds’ nests" [J. Travel & Nat. Hist. 1 (1868): 73].

Discusses their respective views on birds’ nests, sexual selection, and protection.

Asks why, if brilliant colours of female butterflies are result of protective mimicry, do not males become equally brilliant? CD believes variation in females alone accounts for it, rather than protection.

Submits lists of insects [missing] for correspondent to check whether brightly coloured. Wants to determine whether there is any relation between bright colouring, whether in both sexes or one alone, and an unequal number of males and females.

Asks WED whether Langstaff could make some observations on certain facial muscles in expression.

Discusses rapid replacement of mates among birds. "I begin to think that the pairing of birds must be as delicate and tedious an operation as the pairing of young gentlemen and ladies. If I can convince myself that there are habitually many unpaired birds it will be a great aid to me in sexual selection". Notes rivalry of singing birds.

Heard from George Rolleston of the inherited effects of an eye injury.

Disagrees with A. R. Wallace’s idea "that birds learn to make their nests from having seen them whilst young" ["The philosophy of birds’ nests", Intellect. Obs. 11 (1867): 413–20].