To Albrecht Carl Ludwig Gotthilf Günther   6 March [1860]¹

Dated by the reference to CD’s snake specimens from the Galápagos, which Günther discussed in a paper read to the Zoological Society of London on 24 January 1860 (see n. 2, below).

CD’s catalogue of reptile specimens collected during the Beagle voyage is in the British Museum (Natural History). His ‘Diary of observations on zoology’ (DAR 30 and 31) does not contain descriptions of a Galápagos snake. The letter is a response to a paper Günther had read to the Zoological Society of London in January (Günther 1860). CD may have attended the meeting: he was in London on 24 January (Emma Darwin’s diary) and was keen to discuss the distribution of Galápagos birds with Philip Lutley Sclater, the secretary of the Zoological Society (see letter from P. L. Sclater, [3? February 1860], and letter to P. L. Sclater, 4 February [1860]). In the paper, Günther described a new species of snake (Herpetodryas biserialis, a synonym of Pseudalsophis biserialis, the Galapagos racer) from the Galápagos Islands and stated that it was the only snake found there. Between the date of the meeting and publication of the paper, Günther’s attention was drawn to CD’s record of a different species of snake on the Galápagos (Günther 1860). CD’s letter supplied additional information that Günther appended in a note to his paper (Günther 1860, p. 97 n.): Darwin says in his Journ. of Research., p. 381, speaking on the Zoology of the Galapagos Islands:—“There is one snake which is numerous; it is identical, as I am informed by M. Bibron, with the Psammophis temminckii from Chile.” Although subsequently, in the ‘Erpétologie Générale,’ nothing is mentioned by Duméril and Bibron about the occurrence of P. temminckii, or of any other snake, in these islands, that determination of Bibron may possibly be correct. If such be the case, there are two species of Snakes in that group of islands.

When CD published Journal of researches in 1839, he did not have access to the detailed descriptions of his reptile collection. Thomas Bell, who had agreed to describe the collection for Reptiles, passed the snakes on to Gabriel Bibron (Reptiles, p. vi). Bibron, however, was unable to complete the final part of his Erpétologie générale (Duméril and Bibron 1834–54), and CD’s collection remained undescribed. A pencil note in the back of CD’s copy of Journal of researches 2d ed. (Cambridge University Library) reads: ‘D^r Günter has shown. Zoolog Soc. Jan 24 60 that the snake from Galapagos is distinct from that of St Domingo: American form’. On page 381, in the margin next to the description of the snake, CD noted in ink: ‘No | D^r Güunter says endemic species.’ CD managed to insert a note about the snake in the revised ‘postscript’ added to the new issue of Journal of researches (1860), p. vii: The snake mentioned at page 381, as being, on the authority of M. Bibron, the same with a Chilian species, is stated by Dr. Günter (Zoolog. Soc., Jan. 24th, 1859) to be a peculiar species, not known to inhabit any other country. CD erred in the spelling of Günther’s name and in giving 1859 as the year of publication of Günther 1860.

The specimens in Bell’s possession (see n. 3, above) were given to the British Museum in 1845 (Porter 1985, p. 104). According to Donoso-Barros 1975, p. iii, Günther may have unknowingly described CD’s specimen which, by then, had been for some years in the British Museum collection.