On the Borneo cave exploration.

ARW will send his contribution to theory of origin of man. The vast mental and cranial differences between man and apes, whereas structural differences in other parts of body are small. The problem of explaining diversity of human races along with the stability of man’s form during all historical epochs. Discussion with "Anthropologicals" [following reading of ARW’s paper, "The origin of human races", before the Anthropological Society, 1 Mar 1864].

Response to ARW’s papers on Papilionidae ["On the phenomena of variation and geographical distribution", Trans. Linn. Soc. Lond. 25 (1866): 1–71; abstract in Reader 3 (1864): 491–3],

and man ["The origin of human races", J. Anthropol. Soc. Lond. 2 (1864): clviii–clxxxvi].

The former is "really admirable" and will be influential.

The idea of the man paper is striking and new. Minor points of difference. Conjectures regarding racial differences; the possible correlation between complexion and constitution. His Query to Army surgeons to determine this point. Offers ARW his notes on man, which CD doubts he will be able to use.

On sexual selection in "our aristocracy"; primogeniture is a scheme for destroying natural selection.

[Letter incorrectly dated March by CD.]

Argues the antiquity of the human species because natural selection acts differently with respect to men. Changes in man are largely confined to head and brain. Warfare and sex are very uncertain as means of selection.

Gives CD complete credit for theory of natural selection.

Is beginning his narrative of his travels.

Lyell argues against tracing man as far back as Miocene times. R. I. Murchison’s argument that Africa is the oldest existing land implies that Africa is the place to look for early man.