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Darwin Correspondence Project

To Joseph Augustin Hubert de Bosquet   9 September [1856]1

Down Farnborough | Kent

Sept. 9th.—

My dear Sir

I am much obliged for your very kind & interesting letter.2 I am astonished & delighted at your discovery of a Cretacean Chthamalus. It seems to me a very curious discovery. The fact seems to me eminently worth publishing,3 with a careful & full description & enlarged drawing of the shell. Generally I have not the smallest faith in negative Geological evidence;4 but in the case of sessile cirripedes, the evidence did appear (vide my remarks in Introduct. p. 5 to Fossil Lepadidæ) of some value;5 & now you show that the evidence is worth nothing.

Do insist strongly on the caution requisite in our ever presuming to say when a new group first has appeared on the earth. Are you familiar with structure of recent Chthamalus: I think the woodcut at p. 39 of recent Balanidæ shows well the arrangement of the comparments. See my remark p 172 on the odd fact of no extinct Chthamalinæ having been discovered.6

The drawings you have sent me are beautiful; but I have been so hard at work for two years at other subjects that cirripedes are gone rather out of my head, which could never boast of a good memory. In truth I have not the least doubt that you are far more capable of forming a correct judgment than I am on every point of the subject.

Nevertheless I will just give my impression on one or two points.— I should hesitate greatly about admitting a specimen to be Lithotrya, without I could see the serration on the upper scales of Peduncle (see Pl. VIII fig 3d. Balanidæ)7 for they are of such importance for burrowing: in your fig 1 the tergal margin of scutum seems too simple for Lithotrya: can fig. 2. be a carina; if I understand the drawing


Dated by the reference to Bosquet’s identification of a new species of fossil cirripede, which was described in Bosquet 1857. Bosquet’s letter notifying CD of the discovery seems to have been written well in advance of publication (see n. 3, below).
Bosquet’s letter has not been found. CD had corresponded with Bosquet between 1852 and 1854 about fossil sessile Cirripedia. He was the author of a work on fossil Crustacea (Bosquet 1854).
Bosquet 1857. In the published version, Bosquet named the new cirripede Chthamalus darwinii in CD’s honour. There are two copies of Bosquet 1857 in the Darwin Library–Down, one of which is a presentation copy from Bosquet.
See Rudwick 1974 for a description of CD’s mishaps with ‘negative evidence’ in geological theorising.
The passage in Fossil Cirripedia (1851), p. 5, reads: No true Sessile Cirripede has hitherto been found in any Secondary formation; considering that at the present time many species are attached to oceanic floating objects, that many others live in deep water in congregated masses, that their shells are not subject to decay, and that they are not likely to be overlooked when fossilized, this seems one of the cases in which negative evidence is of considerable value.
The references are to Living Cirripedia (1854). CD had presented Bosquet with copies of his Cirripedia monographs (see Correspondence vol. 5).
A slip for ‘Lepadidae’. Lithotrya is figured on pl. 8 of Living Cirripedia (1851).


On JAHdeB’s discovery of Cretaceous Chthamalus. Cites his own acceptance of negative evidence about Chthamali in Fossil Lepadidae.

Comments on JAHdeB’s cirripede drawings.

Letter details

Letter no.
Charles Robert Darwin
Joseph Augustin Hubert de Bosquet
Sent from
Source of text
American Philosophical Society (138)

Please cite as

Darwin Correspondence Project, “Letter no. 1952,” accessed on 20 June 2019,

Also published in The Correspondence of Charles Darwin, vol. 6