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Darwin Correspondence Project

To J. J. S. Steenstrup   3 January [1852]

Down Farnborough Kent

Jany. 3d.

My dear Sir

I know well that I have no excuse for troubling you, but you once most kindly said you would compare any specimens with Spenglers;1 if you would now do so, it would be a very great favour.

1st. Is the Lepas mitra of Spengler a Conia or Tetraclita of Schumacher;2 that is have the walls of the shell many rows of tubes, like the two valves sent? Is L. mitra white? is it narrowly ribbed like these two valves? If L. mitra be a Tetraclita, then I believe these valves belong to this species.

2d. I send two species of Balani, large & small, adhering together:— are either of these the Lepas purpurea of Spengler or its variety, or again are either Lepas balanoides var b lineis rubris.3 The difference between the two specimens sent, is great: if you will break the larger you will find the walls are not tubular only internally ribbed, & the edges of the radii (= areæ depressæ = areæ interjectæ) are quite smooth; and the margin, as seen without disarticulation, rounded.— In the smaller specimens the walls are tubular & the edges of the radii crenated or toothed. In the larger specimen the anterior valves of the operculum are longitudinally striated or furrowed. Without one specimen of Spenglers be disarticulated, it will be hardly possible to identify the species. My specimens may be destroyed.

In my letter thanking you for your most kind present of Xenobalanus4 I asked you kindly to inform me where the name is published, & the habitat of the species.—

My volume on the Pedunculated Cirripedes will soon be distributed by the Ray Society: I have given, some curious facts, I think, on the sexes of some Cirripedes.—

With the highest respect | I remain Dear Sir | Yours sincerely | C. Darwin To | Professor Steenstrup | The Museum | Copenhagen.

It is quite possible that the specimens sent may not belong to either L. purpurea or balanoides var b. but I think they must.


Lorenz Spengler’s cirripede collection, described in Spengler 1790, is housed in the Zoology Museum of Copenhagen University (see Henry and McLaughlin 1986, p. 4).
CD at first believed that the species which he later named Tetraclita radiata was the Lepas mitra described in Spengler 1790. He remained undecided (see Living Cirripedia (1854): 343–4 n., in which CD discussed the differences between the two). Nonetheless, he stated that Spengler’s ‘description of the opercular valves makes me think this may be the same species.’ The genus Tetraclita had first been named by Christian Friedrich Schumacher in Schumacher 1817.
Lepas purpurea and L. balanoides, var b lineis rubris, had been described and figured in Spengler 1790, pp. 172, 170. CD believed both were members of the ‘extremely common species’ which he named Balanus amphitrite (Living Cirripedia (1854): 240–6). He discussed problems involved in establishing the nomenclature in Balanidae, complaining that ‘when no notice is taken of such points of importance, as whether the walls are permeated by pores, whether the radii are smooth-edged, whether the scuta are striated, it is impossible to identify with any approach to certainty sessile Cirripedes’ (ibid., p. 241). Many of the species of this family therefore have numerous synonyms.


Living Cirripedia (1854): A monograph of the sub-class Cirripedia, with figures of all the species. The Balanidæ (or sessile cirripedes); the Verrucidæ, etc. By Charles Darwin. London: Ray Society. 1854.

Schumacher, Christian Frederick. 1817. Essai d’un nouveau système des habitations des vers testacés. Copenhagen.

Spengler, Lorenz. 1790. Beskrivelse og Oplysning over den hidindtil lidet udarbeidede Slœge af Mangeskallede Konchylier, som Linnæus har kaldet Lepas, med tilsae9niede nye og ubeskrevne Urter. Skrivter af Naturhistorie-Selskabet 1: 158–212.


Asks JS to compare cirripede specimens with those of Lorenz Spengler to establish comparative nomenclature.

Requests reference to article describing Xenobalanus.

Letter details

Letter no.
Charles Robert Darwin
Johannes Japetus Smith (Japetus) Steenstrup
Sent from
Source of text
Det Kongelige Bibliotek, Copenhagen (NKS 3460 4to)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 1469,” accessed on 11 April 2021,

Also published in The Correspondence of Charles Darwin, vol. 5