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Darwin Correspondence Project

To Thomas Campbell Eyton   [30 November 1839]

12 Upper Gower St

Saturday Evening

Dear Eyton

I am very much obliged to you for undertaking to examine the birds I mentioned to you, and I am delighted you feel interest in the task.— I would have sent them earlier, but I have been unavoidably prevented: they go to the Railroad this evening.— They are as follows— 388 Tinochorus—? will you be so kind as to make out the species: 707 I suspect in the muscular stomach, & fleshy covering to nostrils Habits you will find some relationship to the Gallinaceous order.— Journal I shall feel great interest, in hearing to what order its internal p.110 structure and skeleton places it.—1 630 Synallaxis maluroides: habits like our reed-wrens & warblers: is it in structure a Certhia?— 650 Serpophaga albocoronata Gould: a genus allied to Tyrannula.— I do not suppose there will be any interest whatever in its examination.—2 721. Furnarius cunicularius: habits briefly described under name of Casarita in Journal p. 112 722 Opetiorhynchus vulgaris— Genus allied closely to last. 728 Uppucerthia— Genus allied to last.—

I do not think these three genera can be compared with any Europæan forms: their dissection will, I think, be very interesting 1037. Pteroptochos albicollis. (only the carcase 1043 Phytotoma rara—a most curious finch habits like a bull-finch 1050 Trochilus gigas. Habits (p 331). Mr Blyth has some notion about humming birds belonging to very different type in their internal structure.3 1157. Pteroptochos Tarnii. Habits given & of P. albicollis —at p. 352, and 329, of Journal.—

I think these will be well worthy of close examination.— In Swainson’s nonsensical language4 they might be called the gallinaceous type in the thrushes.— 1309. Carcase of the common N. American Rice bird: not worth examination.—

There are two birds without tickets; I believe they are Opetiorhynci.—

I hope you will turn to my Journal & refer to their habits before examining them. If you can let me have your account of these specimens in a month or 5 weeks I shall be greatly obliged: as it is uncertain when I shall publish the next number of the Bird Part of the “Zoology of Beagle’s Voyage”.—

Many thanks for your offer of some gallinaceous birds for dissection. we shall be most happy to examine them carefully & pick their skeletons quite clean.—

Dear Eyton | Most truly yours | Chas. Darwin


In an appendix to Birds (pp. 147–56) Eyton contributed anatomical descriptions of the specimens CD listed. The species is identified by both Gould (p. 117) and Eyton (p. 155) as Tinochorus rumicivorus Eschsch. This is the bird that CD had described in his letter to J. S. Henslow, [c. 26 October –] 24 November [1832] from Montevideo (Correspondence vol. 1) as ‘a happy mixture of a lark pidgeon & snipe … Mr Mac Leay himself never imagined such an inosculating creature’ (see Ornithological notes, pp. 211 n. 3, 278). CD’s specimen numbers refer to ‘Birds &c &c in Spirits of Wine’ (DAR 29.3: 77). CD’s ‘Journal’ references are to Journal of researches.
Eyton’s description is on p. 147.
Edward Blyth argued, correctly, that the similarity between humming birds and sun birds presumed by William Swainson was merely an analogy and that these groups differ fundamentally in their internal structure (Blyth 1838, especially pp. 258, 262, 265). Blyth’s articles were a major source of information for CD’s notes on transmutation during the years 1837–42 (see Sheets-Pyenson 1981, which briefly reviews the literature about Blyth’s influence on CD, including Eiseley 1959, Beddall 1972, and Manier 1978).
A reference to Swainson’s espousal of the quinary system of classification (see Correspondence vol. 1, letter to J. S. Henslow, [c. 26 October –] 24 November [1832], n. 8).


Sends bird specimens for examination by TCE [for Birds].

Letter details

Letter no.
Charles Robert Darwin
Thomas Campbell Eyton
Sent from
London, Upper Gower St, 12
Source of text
American Philosophical Society (17)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 547,” accessed on 26 April 2017,

Also published in The Correspondence of Charles Darwin, vol. 2