Has read THH’s review of Sir Wyville Thomson’s [Introduction to the] Voyage of the "Challenger".

Sends a draft of a letter for Nature [Collected papers 2: 223–4]. He particularly asks THH to decide whether he should include a certain paragraph [see ML 1: 389].

Refers correspondent to Descent for some information on marriage arrangements, and on the mental and moral nature of monkeys.

Sir Wyville Thomson misunderstands natural selection when he says the theory "refers the evolution of species to extreme variation guided only by natural selection". CD demurs at the "extreme variation" and the "only". No one has said evolution depends only on natural selection. CD has adduced many facts on the effects of use and disuse and on the direct action of the environment.