My dear Sir,

I thank you very much for your kind note. Your approval of my scheme will help very much to its completion.¹

I am very glad indeed to hear that you take an interest in my few essays written rather by a learner than a teacher.² In all of them I have tried as far as possible to break down the barrier between Pleistocene and living species, by attaching weight to individual variation, and to results of living under different conditions. Thus the Pleistocene animals utterly extinct amount only to about 10 or 11 out of 56.³

Permit me to add that I feel unspeakably grateful to you for your book.⁴ Without it I should probably have been groping in darkness, and manufacturing species in proportion to my own ignorance. All the men who are working minutely at one branch of Nat. Hist, that I know of, endorse your views as regarding their own peculiar provinces,—Dr Duncan in the corals, H. Woodward in the crustacea.⁵ I dont indeed see how any naturalist can work on any other hypothesis. It is cropping up continually even in Prof. Owens works.⁶ If I can add only one grain of proof to its truth, I shall feel amply rewarded for any quantity of labour.

When I was working at the hyænas, I was struck by the wonderful effect that captivity has had in modifying the shape of the skull. The prehensile character of the jaws is to a certain extent lost, and the maxillaries, and rami become shortened in a remarkable degree. Indeed for purposes of comparison I find the bones of animals from menageries absolutely useless. I mention this because it shows how very pliant even the skeletons of animals are, and how with the disuse of a muscle, its points ‘d’appui⁷ become aborted.

I am | My dear Sir | Yours very truly | W. Boyd Dawkins

Charles Darwin Esq.