Discusses names and distributions of Pacific shells. [Lists by CD and Edward Forbes record names and ranges of shells collected by HC in the Galapagos.]

Answers CD’s queries about the number and distribution of species in certain fish genera.

CD’s criticism of his book [Travels in North America (1845)].

Compares invertebrate animals of Tasmania and England.

Mentions views of C. J. F. Bunbury on climate of the Carboniferous period.

Robert Brown says Australian flora has the widest range.

JDH’s grandfather’s death.

Collecting testimonials for the Edinburgh chair.

The most experienced botanists argue for the "validity of species in nature". Against taxonomic "splitters".

CD’s Cape Tres Montes plants.

Thanks for Journal of researches.

Puzzled over pea flower from Cape Tres Montes.

Thinks species a fair and most profitable subject for discussion, but has no formed opinion of his own.

Sends a list of the work he feels should be done at Beesby [Lincolnshire] to put the farm in order. Hopes to get purchase deeds completed by 10 October.

Answers CD’s queries arising from Flora Antarctica.

Would like CD to come to town and go over Galapagos plants with him.

Lateral teeth in Arcadae.

Gives CD page references [in The new statistical account of Scotland, vol. 14, pp 446, 507] for information regarding parallel roads.

Note on editorial details concerning names of fossil shells [for South America, appendix]. The Latin for "Darwin" is "Darvinius".

Describes his reasoning in classifying CD’s Turritella ambulacrum specimens into two sorts. GBS holds that distinguishing characters, whether of species or varieties, should always be noticed. [See South America, appendix, pl. III, fig. 49.]

Sends identifications of CD’s Bahia Blanca fossil shells [see 830].

Goes on the assumption that each species has one origin, is immutable, and migrates.

Disagrees with Gaudichaud[-Beaupré] that volcanic island species are polymorphous.

Some mundane genera vary, others do not (Senecio vs Gnaphalium).

John Lindley’s doctrine of longevity of trees is amazing.

Edward Forbes’s health is better.

Gives his opinion on the tropical character of fossil shells listed by CD. The shells of Navidad [Chile] are not particularly tropical.

Answers CD’s objections with botanical and geological arguments supporting the existence of an ancient post-Miocene land extending over what is now the Mediterranean and past the Azores in the Atlantic [EF’s "Atlantis" theory in "On the connexion between the distribution of the existing fauna and flora of the British Isles and the geological changes which have affected their area", Mem. Geol. Surv. G. B. 1 (1846): 336–432].

Thanks for Edward Forbes’s letter. Botanical evidence conflicts with parts of his theory but supports others. Is becoming more of a migrationist.

Bentham agrees with JDH on polymorphism.

Describes Infusoria in Rio Gallegos samples.

"Fluthgebiete" means estuary deposit.

Discusses dust samples from Malta. Asks for further samples.

JDH recognises the existence of "altered states" of continental species in island floras. The botanists’ difficulty in determining a new species is no grounds for dismissing the important question of altered forms.

Will look for Ascension plants for Ehrenberg.

French Galapagos collections confirm JDH’s view that plants arrived from north.

Cannot agree with Forbes on North Atlantic flora.

Botanical definition of "highness" and "lowness" usually means complexity and simplicity.

Some plants, such as aquatic ones, are cleistogamous. Cannot see why they should not be.

Sends specimens of grasses from Ascension Island for CD to forward to Christian Gottfried Ehrenberg.

Includes list of indigenous flowering plants of Ascension Island.