My dear Sir

I have been truly sorry to have delayed so long in sending the pamphlets,¹ but it has not been my fault, or indeed anyones, as Prof. Bell has been delayed unavoidably in getting them together. I shall now send next Wednesday, through Delf all that I have collected from Bell, A. White & Baird: M^r Westwood had intended sending some, but the death of his Father has interrupted him. D^r. Baird will also send a copy of his volume on British Entomostraca² through Delf.—

I thank you most sincerely for the full answers to all my queries, & I feel somewhat ashamed at the length of them. I am particularly obliged to you & D^r Gould for the Coronula denticulata & even more for Scalpellum, which genus has revealed to me a wonderful story,³ but it is too long here to tell you.— I have written to D^r. Mantell⁴ about these specimens.— Thank you also for telling me about your notice on my Geology in American Journal,⁵ which I did not know of.— I always wait for several years, & then read up each Journal in mass— I have read all the early volumes of this excellent periodical.—

Will you be so kind as to give my sincere & respectful thanks to D^r. Pickering;⁶ I am particularly interested on Geograph. Distrib in Pacific & shall hereafter have occasion to use the list, which shall be shown to my excellent friend D^r. Hooker when he returns from his Botanical tour in India.—

I wished to know about boring crustacea in relation to boring cirripedia.—⁷ With respect to the oviducts, it is almost too long a story:⁸ they do not debouch near the antennæ, but a duct does which I believe is homologous with the oviduct of other Crustacea. This duct is the grand characteristic of Cirripedia, a sticky substance or tissue (for I hardly know which to call it) comes out of this duct from a gland & fixes first the anterior part of head of the larva & subsequently of the mature cirripede to whatever substance it becomes attached.— I have not published this yet, except in a very brief notice in Athenæum of a short speech which I made at the British Association Meeting at Birmingham;⁹ —I have, however, worked out my observations in considerable detail.—

What you tell me of the minute crust in the Creusia, makes me think you w^d like to have & describe some specimens which I will send with the Books. Goodsir (poor fellow I fear he must be called the late Goodsir being with Sir J. Franklin)¹⁰ described in Eding. New Phil. Journal July 1843) a parasite, which he considered the male Balanus:¹¹ this is quite an error; his male Balanus is a female, of which I send specimens gorged with ova containing larvæ: his parasite is, I believe, the male of this female, as the character of the little larvæ show, & comes near to Ionus (NB it is pretty this paratism, considering that cirripedia are crustacea).¹² My specimens I find have been rather injured by mould, but I think you will be able to clean them. I found them attached & parasitic within the so-called sack of a Balanus (from South Wales) with a membranous basis which is the commonest British species on tidal rocks— British authors often call it (I believe incorrectly) Balanus punctatus— one of its varieties is Lepas elongatus of old authors.— Though M^r Goodsir was wrong about this case, I may remark as an odd fact, that I have 3 species in two genera of bisexual cirripedia, with the males parasitic on the females; in one of these cases there are always 2 males to one female, the males being lodged in little pockets in the shell of the female!¹³ The compound animal is a real case of Diandria monogynia¹⁴ in Animals!!

Yours most sincerely obliged | C. Darwin

P.S 1 | I have lately been working at fossil Secondary Pedunculate Cirripedia— Have you ever heard of any having been found in America?

P.S. 2. You will see in next number of Geolog. Journal, that Sir C. Lyell has read your volcanic Chapters & he was very much interested by them.¹⁵