Determined to make GRW a geologist. Sends copy of C. Lyell [?Elements of geology (1838)].

Thanks GRW for collection [of insects] he has made up for CD’s nephew.

Leaves decision to GRW as to which institutions should receive CD’s Beagle insects.

Testimonial letter for GRW for position at British Museum.

Classification consists of grouping beings according to descent from common stocks. Analogies are resemblances between forms not inherited from common stocks. Neither number of species nor grade of organisation should be considered in classification. Admits that caution is necessary in admitting a few species to form a group of rank equal to one containing many species.

Has no objection to uniting Monotremata and other marsupials but would object to doing so solely on ground that Monotremata consists of only two species. Members of a natural group need not share common character so long as they are linked with those which do. Believes that if every organism that ever lived were collected, a perfect series would be presented. What are reasons that unite Aptera and Diptera?

Congratulates GRW on appointment to position at British Museum.

Comments on GRW’s paper [Rep. BAAS (1843): 65–7; Ann. & Mag. Nat. Hist. 12 (1843): 399–412]. CD says by "link" between any two groups he never understood a half-way link, merely one in a long series. Observes that one cannot have a simple species intermediate between two great families. Criticises GRW’s use of circles to represent groups, which leads to thinking that groups are of equal value.

Invites GRW and his family to visit.

Thanks him for describing the niata ox.

He is delighted that GRW is grappling with Galápagos insects. Needs to know immediately whether any entomologists beside GRW, Walker and A. White have described his insects.

Invites GRW to a dinner party with other scientists.

Wishes to propose John Lubbock as a member of the Entomological Society.

Asks for B. H. Hodgson’s pamphlet on sheep ["Tame sheep and goats", J. Asiat. Soc. Bengal 16 (1847): 1003–26]. Asks for odd numbers of GRW’s work [A natural history of the Mammalia (1846–8)]. Regrets that this work has stopped.

Knows no one in Buenos Aires. Suggests sites in South America where Auguste Bravard can find fossils.

Ray Society has delayed distribution [of Living Cirripedia (1851)].

Thanks GRW for his sympathy on his ill health. Feels better lately.

Sends thanks to G. P. Deshayes for his advice.

Asks what "original work" GRW has begun so his name will become better known.

Sends fossil cirripedes for the museum’s collection.

A page of [unspecified] text is missing from a parcel of material received from GRW.

CD "hopes and expects to live to see Carboniferous, & perhaps even Silurian, mammifers!"

Has several questions to ask whenever they meet.

Asks GRW if there is any easy systematic work on Lepidoptera for his sons. Considers making out the names from descriptions fine practice for the intellect; mere collecting is idle work.

Has no drone cells in collection of honeycombs. Discusses construction of cells by bees and ability of bees to judge distances in constructing comb.

Returns a letter from a Mr Walsh – "a clear-headed man on my side". What he says about sea trout in lochs would make a good case for CD if borne out by professional ichthyologists.

Wishes to know the correct name for the British Museum’s specimen of an Abyssinian wolf described by Wilhelm Rueppell, Neue Wirbelthiere zu der Fauna von Abyssinien [1835–40] .