Dear Sir

I am sorry that my last letter of enquiry was sent, for the very next day I received your very interesting letter and magnificent present of fossils;¹ I truly hope that you have not robbed yourself: ultimately your specimens shall be deposited in the British Museum. I am astonished at the industry you have shown in collecting so many and perfect specimens, and in the great skill shown in the determination of the species. I happen to be too much occupied to give as much time as I should like to studying your specimens; but after a pretty careful inspection, I am quite inclined to agree with almost all your determinations, and I can feel no doubt that the species considered by you as new, are new. Indeed I consider it as in some degree presumptuous in saying this; for you are evidently an adept amongst the Cirripedia. I will take the subjects in the order of your note:—

Verruca pisca.² My specimen was procured at Norwich;³ and M^r. John Morris⁴ believes the chalk at this place belongs to a high stage; but the precise bed is not known. I think my specimen is the same as yours; but Verruca can hardly be recognised without the specular⁵ valves. V. pisca differs very little from V. Strömia; but the surface of the shell is not ridged longitudinally; and the movable scutum resembles that of V. lævigata in the lower articular ridge being broader than the upper articular ridge. The plate for the adductor muscle in the fixed scutum, has I think, even in your best specimen, been broken; you will, I think, see discoloured lines of growth, which will show the true outline: I return this valve with very sincere thanks. There seems to me nothing particular in any of the other valves. I am not surprised at hearing Poll-validus = P. gracilis.⁶ With regard to Scalpellum maximum var. being identical with S. fossule, I cannot help doubting it:⁷ I examined several specimens of the carina and saw no gradation in character: moreover the other valves seemed to me distinct. I possess only a single and broken carina and cannot give it you, but I send it for you to look at: be so good sometime to return it. I agree with the valve marked Rostrum being so. With respect to the number of the valves in some species of Scalpellum, I feel greater doubts, even than when I wrote the note (p. 254), to my Recent Lepadidæ.⁸ I hardly think the Latus Tab. II, fig. 4 of my Fossil Lepadidæ can be an upper Latus: please look at the valves in my Scalp. fossiles (and your Scalp. Maximum) in which the valves can be positively named.

Mitella Darwiniana ⁹ (you have done my name much honour) I think rather strongly from what I have seen of recent species, that the small “valves spiniformes” and have come from the peduncle: this appears a very good species.

Scalp. Darwinianum:¹⁰ I daresay the narrow valve sent may be a rostrum; but the valve most like which I have ever seen, is the carina of the eocene Pollicipes reflexus. How singular a valve is the Rostral Latus! but some suspicion crosses me that it may be an Upper Latus.

Sc. pulchellum:¹¹ I should have rather strongly thought, the valve called by you Latus infra-median was a Rostral Latus. Both these latter species seem very interesting forms. Again let me express my sincere thanks for your most kind present, and my great respect for your excellent labours. I can assure you, I never expected to hear of anyone taking the trouble so thoroughly to understand my volumes as you have done: and it has been a very high gratification to me.

With very much respect believe me, Dear Sir, Yours very faithfully | Charles Darwin