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Darwin Correspondence Project

From Richard Bishop to Charles Spence Bate1    3 December 1857


Decr. 3. 57.

My dear friend,

I have much pleasure in answering, to the best of my power, the inquiries made by Mr Darwin respecting the impregnation of the Balanus;—had I known that the observation was new, or could possibly possess so much interest as your esteemed correpondent attaches to it, I would certainly have watched the process more critically.2 I can only hope on some future occasion to be enabled to supply more precise information, if some other observer should not forestall me.

To take Mr Darwins queries seriatim—

1st. The Species —Balanus communis?

2nd. Was the penis inserted into more than one individual? not positive , but I believe it was. It was extended to a length equal to about 3 times that of any single branch of the cirrus, & waved in every direction till it came in contact with the cirrus of a neighbouring balanus, when it was inserted, I believe into more than one. It should be observed that my group is not large, consisting of only 5 full sized animals & a few small ones.

3rd The insertion did not occupy more than 2 or 3 seconds.

4th. Not inserted deeply as far as I could judge— at which end of valves was not noticed.

5 & 6. My own impression is decidedly, that the recipient individual was during the time exerting its cirri, with more than usual energy, & gave evidence of the intruder being a welcome guest, but on these points my memory is unfortunately not supported by that of a friend who joined me in noticing the act.

7. The specimens were under water at the time, I have not under other circumstances seen any movement of the cirri.

The particular instance referred to occurred on a fine bright day, about 3 months ago, when the sun was shining full on my glass, and the specimen had been recently taken & was in full vigour. The group still appears healthy, but I have not since observed a repetition of the indulgence of its amatory propensities. Is it a question of season ?

I remain | yours sincerely | Rd. Bishop Spence Bate.

CD annotations

Top of first page: ‘Ch 3’3 brown crayon


CD had corresponded with Charles Spence Bate when CD was preparing his monograph on the Cirripedia (see Correspondence vol. 5). Bate had apparently written to CD about Bishop’s observations (see letter to Asa Gray, 29 November [1857]) and subsequently transmitted Bishop’s response to CD’s queries.
CD had previously found only indirect evidence to suggest occasional cross-fertilisation between individuals of the hermaphrodite cirripede Balanus balanoides (Living Cirripedia (1854), p. 102).
The annotation refers to CD’s chapter ‘On the possibility of all organic beings occasionally crossing’ (Natural selection, pp. 35–91), in which CD discussed the possible pairing of hermaphrodite cirripedes like Balanus balanoides. The case given by Bishop was not, however, cited in CD’s discussion here (Natural selection, p. 45) nor subsequently in Origin.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

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.

Natural selection: Charles Darwin’s Natural selection: being the second part of his big species book written from 1856 to 1858. Edited by R. C. Stauffer. Cambridge: Cambridge University Press. 1975.

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.


Gives observations to be forwarded to CD of impregnation in Balanus.

Letter details

Letter no.
Richard Bishop
Charles Spence Bate
Sent from
Source of text
DAR 160: 189
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 2179,” accessed on 31 July 2021,

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