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Darwin Correspondence Project

To Samuel Pickworth Woodward   21 March [1850]

Down Farnborough | Kent

March 21.

My dear Sir

I am extremely much obliged to you for taking the trouble to give me so clear & succint a resumè of the history of Aptychus1 with your capital little sketches. I will come sometime to the Museum, & beg you to show me some specimens.— The facts you state (& a few specimens seen by me) appear to me to render d’Orbigny’s view, a priori, so improbable, that I hope a very short inspection will suffice for me.—2 I am far from anxious to drag anything into Cirripedia; with my small powers of work the order is now enough & too much for me.—

The (3) specimens which you gave me from Norwich were very useful to me, & well exemplify Pollicipes maximus & sulcatus of Sowerby, which I consider varieties of one species of Scalpellum.—3 The two specimens from the Grey Chalk have turned out very interesting: one I have described as a new species,4 & the other is a very rare one, seen by me only in Mr Bowerbank’s collection.5 I will take care of all, hereafter to be returned to Brit. Mus.—

I have not heard from the Dover man, & I fear you have not heard from the Norwich collector.— I am very sure dozens more species of Cirripedia will turn up— I wrote from your suggestion to Mr Tennant6 & he has most kindly lent me his collection, which contains 2 valves quite new to me.

Your’s very sincerely | With thanks | C. Darwin

Kind remembrances to Waterhouse


In CD’s time, Aptychus was considered a genus of some fossil organism and constituted a biological puzzle. It is now known to be a horny plate or lid found in fossil ammonites.
Alcide d’Orbigny maintained that Aptychus was a pedunculate cirripede (Orbigny 1849–52, 1: 254–7). CD argued against this view in Fossil Cirripedia (1851): 3–5. He believed there were good morphological reasons why Orbigny was wrong. But in addition to this he suggested a reason which, he said, ‘will have weight, perhaps, with only a few persons’ (p. 4). The fossil, which has upward-directed ‘valves’, occurs in the Carboniferous formations, much earlier than the earliest known cirripede, Pollicipes. In the latter the direction of the valves is downward. Upward direction in valves occurs only in late Tertiary cirripedes. Thus if Aptychus were a cirripede it would occupy an anomalous place in what CD called the ‘order of creation’, and would violate what he elsewhere referred to as ‘the law of relation between serial affinities of animals and their first appearance on this earth’ (‘British fossil Lepadidae’, Collected papers 1: 252; see also Fossil Cirripedia (1851): 5). CD saw a close relation between the age of fossil Lepadidae and the upward or downward direction of the lines of growth in their valves.
Probably Scalpellum hastatum (Fossil Cirripedia (1851): 37).
No Grey Chalk specimen from Bowerbank’s collection is listed in Fossil Cirripedia (1851). It is possible that CD refers to specimens of a variety of Scalpellum arcuatum, although he stated that the two specimens came from the British Museum and John Wickham Flower respectively (Fossil Cirripedia (1851): 41–2).
James Tennant, professor of mineralogy, King’s College, London. In the preface to Fossil Cirripedia (1851), CD mentioned Tennant among those who supplied him with specimens of species that were new to him. The valves were identified as coming from Pollicipes bronnii (ibid., pp. 77–8).


Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.

Fossil Cirripedia (1851): A monograph on the fossil Lepadidæ, or, pedunculated cirripedes of Great Britain. By Charles Darwin. London: Palaeontographical Society. 1851.

Orbigny, Alcide d’. 1849–52. Cours élémentaire de paléontologie et de géologie stratigraphiques. 3 vols. Paris: Victor Masson.


Thanks SPW for his history of Aptychus, which makes A. D. d’Orbigny’s view [that it is a cirripede] improbable. [See Fossil Cirripedia 1: 3.]

Specimens SPW sent are very useful and interesting.

Letter details

Letter no.
Charles Robert Darwin
Samuel Pickworth Woodward
Sent from
Source of text
Barbara and Robert Pincus (private collection)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 1314,” accessed on 26 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 4