My dear Sir,

As soon as I finished the Examinations (Nat. History) in the Edin^r. University I perused your most suggestive work on the worms, & I now see how valuable it will be not only to the public—but to men of science, & especially to workers amongst the Annelida.¹

So far as I see the ingenuity of the marine worms far surpasses that of the Lumbrici in regard to the powers of boring & the “finish” of their dwellings.²

The tubes formed by the marine annelids are not only complex but beautiful; just as their varied colours vie with those of the butterflies &^c.

If you saw the marine annelids at work, you w^d. not doubt how easily the earthworm could reverse itself in its burrow.³

I quite agree with your views in regard to the part played by the Lumbrici.⁴ They likewise play a great part in making the humus on the surface of gravel—as here.

I shall find your work of much service when I return to my favourite British Annelids. At present, as I daresay you know, I am busy with the ‘Challenger’ Annelida, & the work is serious. I shall have abt. 100 4to plates. Sixty are already engraved.⁵

Enclosed is a note which may be interesting to you. Kindly return it after perusal. Prof. Crum-Brown, F.R.S, is Prof. of Chemistry in the Edin^r. University.⁶

Again thanking you for your valued gift—which I cherish much,

Yours sincerely | W. M^cIntosh.

Chas. Darwin, Esq.^r of Down, | L.LD., F.R.S &c &c

P.S. | The Edin. chair of Natural History will soon be vacant, and I shall probably once more try for it.⁷