Encloses a testimonial for GWC [see 6162]. Feels himself poorly qualified to give a testimonial for a botanist and apologises for his brevity.

Asks about the ratio of male to female Lepidoptera.

Thanks JJW for his great assistance.

Discusses sexual selection in birds.

Sends queries on secondary sexual characteristics of birds.

Has often marvelled at the different growth of the flowering and creeping branches of ivy.

Thanks CD for testimonial.

AG’s review of Variation [Nation 6 (1868): 234–6] very good.

CD’s fondness for Pangenesis; although an "infant cherished by few", CD expects it to have a long life.

Sends his notes on Florent Prévost’s reference to the habits of the cuckoo.

Answers CD’s queries on difference in size of male and female Scottish deerhounds; female preference for larger males; details about ratio of sexes born. Quotes from letter of Archibald McNeill on difference in size of male and female Scotch deerhounds.

Returns volumes of the Ibis.

Requests T. C. Jerdon’s Birds of India

and Thomas Bell’s British reptiles

as well as vols. 5 & 6 of Ibis.

Sends proofs of his fish paper.

Will observe modification of colour in fish.

Is studying the development of the axolotl.

Encloses notes in reply to CD’s queries on fishes.

WDF’s letter gives CD the kind of facts he wants. His story about peacocks is so good that CD will quote it [Descent 2: 46].

Pleased WDF approves of his book [Variation]

– "beloved Pangenesis disagrees badly with many".

Asks CD’s permission to translate Variation into Italian [translation not published until 1876].

Has often thought CD would find vast material for his ideas in study of entomology and Lepidoptera. His price-list of specimens proves only that collectors of Lepidoptera catch more males than females, not that there are more. He accounts for this by the less active habits of the females. [See Descent 1: 312.]

On false claims that female cattle can be produced at will.

Asks function of several twisted parts (stem, petals, germen) in hardy orchids. His reading of Orchids makes him suspect that the parts are connected with fertilisation.

Raises a question about a statement in Orchids; his observations differ.

Has passed on copy of Variation to American Academy [of Arts and Sciences]. The U. S. reprint is not very nicely printed.

Replies to CD’s queries regarding sexual differences in gibbons’ voices, chameleon behaviour, and the occurrence of spurs in pheasants and peahens. Discusses sexual differences in structure and habit within certain bird species.

Answers CD’s question on whether any female birds regularly sing.

Sends graft-hybrid notice.

Is confirmed about the bending of the fly orchid pollinia. [See "Fertilisation of orchids", Collected papers 2: 141.]