To A. A. Gould 20 August 
Down Farnborough Kent
I did not receive your very kind note of April 30th & loan of Cirripedes through Mr Cuming until a fortnight since; for I have been absent from home & all my work interrupted for the last five months. My health became so exceedingly bad, that I could do hardly anything, & I consequently have been to Malvern & tryed the Cold Water Cure under Dr. Gully with great success. I am now at the Cirripedia again, but am allowed to work only two hours a day: I feel truly grateful for your kindness in assisting me: the sessile Cirripedes will come in very useful, when I come to that division,1 & they shall hereafter be carefully returned to you: I believe I told you that I require to disarticulate a specimen of each species; without this being done it is impossible to describe or recognise the species: I trust you will not object to this; should you do so, there will be time to inform me. The Ibla is a species (not published) which I have named I. Cumingii & was found in numbers by Mr Cuming at the Philippines: I have never seen it from elsewhere, except the specimen from Tavoy sent by you:2 it is in some Anatomical respects, perhaps the most interesting cirripede in the world.3
I will send the Scutella to Mr Gray at British Museum, as directed.
I have acted on your kind suggestion & written to Mr Dana
You say “that I have figures & notes of 3 or 4 species of Anatifa which I cd copy for you if desired”: if you could let me have a specimen of such those figures & notes would be of the greatest service to me, but without you have minutely described the internal surface of the valves, & the Branchiæ of the animal, I find it quite impossible to recognise species of Anatifa. I see in the drawing sent the colours are marked specimens of such wd be invaluable, for then I shd know the colouring.—
I thank you most cordially for your offer of further assistance: from my health & the extreme difficulty of describing the species, I shall certainly be employed a year or two more on the Cirripedia—
Could you tell me in what works Mr Conrad4 has described or is likely to have described Cirripedia: in Mr. Cumings collection there as 2 or 3 species (especially a Pollicipes from California) named by him & I am quite at loss to know where to look— Of course I do not intend for one second to hint to you to take the trouble to search for references; but as you have attended so much to shells you may be able to guide me where to search.— I wrote to Mr. Conrad myself on this subject, but either my letter miscarried, or he thought I took too great a liberty in addressing him; anyhow I have had no answer.—
With my sincere thanks | Believe me | Your’s faithfully & respectfully | C. Darwin
If you ever see an Anatifa adherent to a Crab, you may be almost sure it will be new & interesting: there are several species, which I have been compelled to separate under a new generic name:5 I am glad to say that I have had to run far more genera together, than to separate & make new ones.—
Thanks J. D. Dana for cirripede specimens. Describes his work. Comments on Ibla. Would like to see AAG’s notes and figures on Anatifa. Asks for references to cirripede descriptions by T. A. Conrad.