To Robert Fitch 1 February 
Down Farnborough Kent
As this is the first of Feby. I write to report progress. I have lost 5 days by my own unwellness & the illness of one of my children.— On every other day, without exception I have worked 2 hours (which the Doctors only allow me) on fossil Cirripedia. I believe I have now about 200 specimens in the house & the labour of comparing so many valves (many of which I have to clear out of matrix & repair) is great.
I have described eleven species in detail & next Wednesday I take up many specimens to be drawn.—1 I suppose I have at least 12 more species to describe, of which several belong to you.—2 I cannot work quicker, but I pledge myself to go steadily on with the fossil pedunculate species till they are finished.—
Please to observe that where there are many valves each species requires 5 or 6 pages of description.—
From the kindness of your notes, I do not believe you will object to my keeping your specimens somewhat longer—if I do not hear I shall understand I have your permission.—
Yours faithfully | C. Darwin
I forgot before to say that all your specimens shall be returned named specifically & with name of valve
Describes work on fossil cirripedes. Asks to keep specimens somewhat longer.