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Darwin Correspondence Project

To Albert Günther   25 February 1874

Down, | Beckenham, Kent.

Feb 25 1874

My dear Dr Günther

I have given, in my Descent, vol. 2. p. 12, an account from you of the curious brushes on the sides of the 2 sexes of Monacanthus.1 Now you no doubt will have seen an acct in the American Naturalist (1871 p. 119) of the brush-like scales with which the males alone of Mallotus villosus are provided, by which apparently 2 males hold the female during the act of spawning.2

Now will you be so kind as to tell me to what families the Monacanthus & Mallotus belong; that is, whether they are allied? Am I right in supposing that the use of the brush-like males is the same in these 2 genera?

I shd be very much obliged for any information & remain | yours sincerely | Ch. Darwin

It seems that with many Cyprinidæ two males attend on one female; what an odd anomaly this seems to be.—3


Monacanthus is the genus of file-fishes; CD had discussed the brushes in the context of sexual differences.
The unsigned note, ‘Spawning of the capelin’, appeared in American Naturalist 5 (1871): 119–20. It is scored in CD’s copy in the unbound journals collection in the Darwin Archive–CUL.
Cyprinidae is the family of carp and minnows. CD had mentioned this behaviour in Descent 1: 308–9.


Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.


Has given in Descent 2: 12, an account from AG of the brushes on the sides of Monacanthus; has now learned of brush-like scales on the males of Mallotus. Asks whether the two genera are related.

Letter details

Letter no.
Charles Robert Darwin
Albrecht Carl Ludwig Gotthilf (Albert) Günther
Sent from
Source of text
Shrewsbury School, Taylor Library (38)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 9315,” accessed on 5 March 2021,

Also published in The Correspondence of Charles Darwin, vol. 22