CD is distressed that JS’s shipment of fossils has been lost: "of all the Cirripedes in the world, I most wish to dissect the Alepas squalicola". Welcomes JS’s offer to send some northern recent species. CD finds great confusion in the current classification of cirripedes in British museums; different genera are made into one species, mere varieties are made into distinct species. If JS would give him some named common northern species, it would be of great assistance.

Thanks JS for fossil cirripedes. Discusses the specimens. Sends thanks to J. G. Forchhammer for specimens.

Describes progress of research on fossil cirripedes. Comments on specimens sent by JS. Asks about age of several European formations, and for information about specimens.

Describes progress in illustration of fossil cirripede specimens. Thanks for answers to questions. Comments on hermaphroditism. Describes his discovery of parasitic male cirripedes.

Asks him to send additional cirripede specimens.

Fossil cirripede specimens have arrived.

Describes progress on his monograph [Fossil Cirripedia].

Would be grateful for the paper on Lithotrya. Asks for information.

Thanks for fossil cirripede specimens.

Describes progress on his book [Fossil Cirripedia] and his work on living cirripedes. Asks to borrow specimens.

Comments on book [F. C. L. Koch and Wilhelm Dunker, Norddeutschen Oolithgebildes (1837)].

Sends thanks to Friedrich Adolph Roemer and R. A. Philippi for specimens.

Fossil cirripedes specimens being returned. Will send a copy of monograph [Fossil Cirripedia]. Discusses work on recent cirripedes.

Returns fossil cirripede specimens to WD, Friedrich Adolph Roemer, R. A. Philippi, and F. C. L. Koch.

Collection of recent cirripedes received. The fossil cirripedes have been returned.

Returns fossil cirripede specimens to JS and Forchhammer.

Sends copies [of Fossil Cirripedia] to them and to Sven Lovén.

Reading proofs [of Living Cirripedia].

Thanks him for specimens of Xenobalanus. Discusses systematic relations of the genus.

Comments on paper by J. T. Reinhardt ["Om slaegten Lithotryas", Vidensk. Medd. Naturhist. Foren. Kjobenhavn 2 (1850): 1–8].

Asks for reference to publication about Xenobalanus.

Asks JS to compare cirripede specimens with those of Lorenz Spengler to establish comparative nomenclature.

Requests reference to article describing Xenobalanus.

Offers to send collection of cirripedes to Copenhagen Museum in return for assistance in his research. Mentions publication of Living Cirripedia, vol. 2.

Thanks GC for his assistance. "The data for all that I have to say about the Scotch deer-hound are, owing to you, almost sufficient; and much better data than I have got in many other cases." [See Descent 2: 260.]

Believes Dr Stirling would be compelled to admit some change in "the famous protoplasm in our domestic races, both in regard to the structure of the body & qualities of the mind".

"With kind regards, & many thanks for Prof. Steenstrup’s Photograph, which is most highly valued by C. Darwin"

Sends his autograph.

Thanks AB for his paper on the Norwegian flora ["Forsög til en Theori om Invandringen af Norges Flora", Nyt Mag. Naturvidensk. 21 (1876): 279–362]. Appears to CD to be the most important contribution towards understanding the present distribution of plants since Edward Forbes’s essay on the effects of the glacial period ["On the connexion between the distribution of existing fauna and flora of the British Isles and the geological changes which have affected their area", Mem. Geol. Surv. Engl. & Wales 1 (1846): 336–432].

Thanks for a letter describing variation in chickens.