My dear Gray

You are aware that I have been attending for the last 14 months to the anatomy of the various genera of Cirripedia. Having, as I hope, now acquired a fair knowledge of their fundamental structure, it is my intention to publish a monograph on this difficult order.² The object of this letter is to ask you to request the permission of the Trustees to describe the Public collection of the Museum. This, however, involves the absolute necessity of my having the collection, not all at once, but in groups at my house here. I find by experience that each species takes me between 2 & 3 days, & each new genus, as many weeks. Every portion requires examination under the microscope & all the minuter organs under a high compound power: the shells also, require soaking & cleaning. I have resolved not to describe any species, without I can do it thoroughily. I am well aware that my request in an unusual one; but I would most respectfully beg to call the attention of the Trustees to the fact that specimens are sent out to be mounted, & that one specimen of every species of Cirripede must be disarticulated for the characters to be ascertained, & the parts of the mouth dissected. The portions thus dissected I prepare in spirits between two plates of glass. If the Trustees think me worthy of their confidence I will give to the Museum all such preparations, (whether made from my own or the Public collection) & all my entire shells (including many new species), as soon as my work is completed. I would further beg to call the attention of the Trustees to the fact, that their entire collection, (contained in 8 or 10 drawers) will thus be named & arranged without the loss of the valuable time of the Officers: though I fully believe that you could do the work in half the time I could, yet I am convinced that to examine & classify the public collection in the Order, as it should be done, would take a year.

In case the Trustees are inclined to do me the honour of acceding to my request,³ I pledge myself to take the utmost care of the Collection & to do nothing whatever to the specimens, without your express permission.—

I will only further add that M^r Cuming & Stutchbury⁴ & yourself have placed their most valuable collections at my disposal for description, & that I have a fair collection of my own.—

How much a monograph of this Order is wanted, you, who know it far better than any man in England, are well aware. In fact the whole of the species are in almost a compte state of chaos: as Agassiz has remarked, a “Monograph of the Cirripedia is now a pressing desideratum in Zoology”.⁵ How far I am capable of this undertaking you must decide; if I fail it shall not be for want of labour.

I apologise for the length of this letter, & beg to thank you for the kind assistance you have already given me.

I remain | Yours very faithfully | Charles R. Darwin To J. E. Gray Esq^e