skip to content

Darwin Correspondence Project

From William Duppa Crotch   25 January 1861

Uphill House | Weston Super Mare

Jany 25th/61

Dear Sir,

Suddenly after the first written date1 I went to Berlin to work out some difficulties in the Hemiptera—2 I had just returned from Shetland, & had gleaned two facts interesting to you, as I hope— The Shetland ponies during winter are much stinted in food & feed largely on sea-weed— as a result their stomach becomes so modified & reduced in size that few physiologists could guess the proprietor to have been a horse— Again it is well known that MacGillivray contended for physiological characters as invariable & affording specific characters when morphological results are useless—3 Could he revive & see the Shetland Sea gulls or rather their membranous crop—that proventriculus on which he gloated—developing muscular fibre & becoming a complete gallinaceous gizzard under the influence of a change of diet from fish &c. to corn: What would he then say of physio- versus morpho-logical char? one wd. change an obvious species, (so called—), the other, so far, wd. preserve it—tho’ it is difficult to say what change some generations of grain diet wd. produce in the external organs—

In Berlin too I learned an important fact, I fancy new. M. Raymond took near Toulon several specimens of an eyeless beetle (Anophthalmus Raymondi) in a cellar belonging to an ancient monastery long abandoned)—4 How did they get there & where from?

Lecturing to unbelievers is grand fun—especially as I find we hit pretty equally hard & when a man knows the thrust in Hybrid I find it difficult to parry & generally reply by a thrust in Selection— But I waste your time—

Yours sincerely | W. D. Crotch

CD annotations

1.1 Suddenly … organs— 1.14] crossed pencil
3.1 Lecturing … Crotch 4.1] crossed pencil


The date was originally written as ‘8 January 1860.’ and then corrected by Crotch.
Crotch, an avid entomologist, had a particular interest in Lepidoptera, Coleoptera, and Hemiptera.
William Macgillivray, a noted systematist, was the author of a standard taxonomic work on British birds (Macgillivray 1837–52).
The discovery of a new species of the genus Anophthalmus by E. Raymond was announced in the Annales de la Société Entomologique de France 3d ser. 8 (1860): li. CD was interested in Anophthalmus and other blind cave animals in connection with his belief that faculties no longer of use to an organism would be likely to degenerate. See Origin, pp. 137–9. His explanation of how this could occur had been called into question by Andrew Murray in 1860, who cited the geographical distribution of species of Anophthalmus as an apparent obstacle to CD’s explanation. See Correspondence vol. 8, letters to Andrew Murray, 28 April [1860] and 5 May [1860], and letter from Andrew Murray, 3 May 1860.


Physiological changes in Shetland ponies and seagulls resulting from change in diet.

Reports on the discovery of eyeless beetles in cellar [i.e., not caves]. How did they get there, and whence?

Letter details

Letter no.
William Duppa Crotch
Charles Robert Darwin
Sent from
Source of text
DAR 47: 173–4
Physical description
4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 3052,” accessed on 18 June 2019,

Also published in The Correspondence of Charles Darwin, vol. 9